POLICY RESEARCH WORKING PAPER 230 9
What Drives Private Saving Saving ratesvary considerably
across countnes and over
around thle World? time. Policies that spur
development are an indirect
but effective way to raise
Norman SchmiatHebba l private saving rates - which
Klaus Schmidt-Hebbel
rise with the level and growth
Luis Serve'n
rate of real per capita income.
The World Bank
Development Research Group
Macroeconomics and Growth U
March 2000
l POLICY RESEARCH WORKING PAPER 2309
Summary findings
Loayza, Schmidt-Hebbel, and Serven investigate the development are an indirect but effective way to raise
policy and nonpolicv factors behind saving disparities, private saving rates.
using a large panel data set and an encompassing Predictions of the life-cycle hypothesis are
approach including several relevant determinants of supported in that dependency ratios generally have a
private saving. They extend the literature in several negative effect on private saving rates.
dimensions by: The precautionary motive for saving is supported by
* Using the largest data set on aggregate saving the finding that inflation - conventionally taken as a
assembled to date. summary measure of macroeconomic volatility - has a
* Using panel instrumental variable techniques to positive impact on private saving, holding other facts
correct for endogeneity and heterogeneity. constant.
* Performing robustness checks on changes in * Fiscal policy is a moderately effective tool for raising
estimation procedures, data samples, and model national saving.
specification. * The direct effects of financial liberalization are
Their main empirical findings: largely detrimental to private saving rates. Greater
* Private saving rates show considerable inertia (are availability of credit reduces the private saving rate;
highly serially correlated even after controlling for other financial depth and higher real interest rates do not
relevant factors). increase saving.
* Private saving rates rise with the level and growth
rate of real per capita income. So policies that spur
This paper - a product of Macroeconomics and Growth, Development Research Group - is part of a larger effort in the
group to understand the determinants of saving in developing countries. The study was funded by the Bank's Research
Support Budget under the research project "Saving in the World: Puzzles and Policies" (RPO 68 1-36). Copies of this paper
are available free from the World Bank, 1818 H Street NW, Washington, DC 20433. Please contact Emily Kline, room
MC3 -341, telephone 202-473-7471, fax 202-522-3518, email address kkhine@worldbank.org. Policy Research Working
Papers are also posted on the Web at www.worldbank.org/research/workingpapers. The authors may be contacted at
nloayza@worldbank.org or Iserven@Cworldbank.org. March 2000. (32 pages)
The Policy Research Working Paper Series disseminates the findings of wvork in progress to encourage the exchange of ideas about
development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than folly polished. The
papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this
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Produced by the Policy Research Dissemination Center
WHAT DRIVES PRIVATE SAVING
AROUND THE WORLD?
Norman Loayza*
Klaus Schmidt-Hebbel*
Luis Serv6n*
KEYWORDS: Private Saving, Panel Data, Internal instruments
JEL classification: E21, C23
* Loayza: Central Bank of Chile and World Bank. Serven: World Bank. Schmidt-Hebbel: Central Bank of
Chile. We thank Orazio Attanasio, Barry Bosworth, Angus Deaton, Michael Gavin, Roberto Rigob6n, Fabio
Schiantarelli, and Jaume Ventura for helpful discussions, and serminar participants at MIT, the Econometric
Society meetings in Lima, Berlin, and Cancun and two anonymous referees for comments on previous drafts.
However, they are not responsible for any errors. We are also grateful to Helmut Franken, Humberto L6pez
and, particularly, George Monokroussos for excellent assistance. The views expressed in this paper are ours
only and do not necessarily represent those of the Central Bank of Chile, the World Bank, its Executive
Directors, or the countries they represent.
2
1. Introduction
Over the last three decades the world has witnessed a marked divergence in saving
rates, particularly dramatic within the developing world: saving rates have risen steadily in
East Asia, stagnated in Latin America, and fallen in Sub-Saharan Africa. These regional
saving disparities have been closely matched by diverging growth experiences: across world
regions, higher saving rates tend to be correlated with higher income growth.
This large variation in saving performance across countries and over time raises a
number of questions. Why do saving rates differ so much across countries and time
periods? How much do public policies contribute to these saving disparities, in comparison
to other structural and non-policy saving determinants?
From the policy perspective, there are serious questions about the size -- and
sometimes even about the sign -- of the effects of policy variables on saving rates. How
effective is fiscal policy in raising national saving? Does financial liberalization -- by
raising interest rates, encouraging consumer and housing lending, and raising financial
depth -- inhibit or encourage private saving? Does foreign lending crowd out national
saving? Or perhaps growth-enhancing policies -- such as macro stabilization and structural
reform -- would be more effective in raising saving through higher income and growth than
any direct saving incentive?
In this paper we address the above questions empirically, by exploiting what we
believe is the largest cross-country time-series macroeconomic data set on saving and
related variables assembled to date. The data set is unique because of various features.'
First, it encompasses industrial and developing countries and covers nearly 30 years of data.
Second, it provides alternative saving measures (for the nation, the central government, the
public sector, and the private sector separately; unadjusted and adjusted for inflation-related
capital gains and losses). Third, it has been subject to extensive quality checks, which
among other things allow us to identify problematic observations and set them aside if
necessary.
The objective of the paper is to use this large data set to establish the stylized facts
concerning the effects on the private saving rate of its key policy and non-policy
determinants identified in the literature. To do this, the paper estimates a variety of
empirical equations for the private saving rate. Private saving regressions are estimated for.
a worldwide sample of countries, as well as separately for industrial and developing country
subsamples. For completeness, the paper also presents regression results for the national
saving rate. In order to encompass a broad range of saving determinants, and hence
theoretical views about saving, we use a variety of reduced-form linear specifications rather
than one narrow model of saving derived from first principles.2 We believe that this
approach provides a useful first step to identify the key empirical regularities in need of
structural explanation.
We estimate our empirical equations using various panel data procedures, paying
particular attention to the issues of simultaneity and country heterogeneity that are mostly
ignored in earlier studies. Specifically, our large panel data set allows the use of "internal"
3
instruments to correct for these problems. This permits us to make some progress towards
drawing inferences on the effects of policy and non-policy variables on private saving rates,
rather than merely describing their association.
The paper is organized as follows. Section 2 summarizes briefly recent cross-
country empirical studies of private saving. Section 3 presents our empirical strategy,
describing the data set and estimation approach. Section 4 reports the econometric results
for the private (and national) saving rate using a variety of samples, regression
specifications, and estimation techniques. The paper closes with brief concluding remarks.
2. Determinants of Private Saving Rates in Previous Panel Studies
Table 1 summarizes potential determinants of private saving rates and lists their
expected signs according to consumption theory.3 A number of recent empirical studies
have estimated the effect of various economic and demographic variables on private saving
rates in cross-country time-series (panel) samples. In order to provide a summary on the
empirical evidence related to each of the saving determinants under consideration, the last
column in Table 1 lists the qualitative results of 6 recent studies using large panel data
samples. They comprise studies for both industrial and developing countries (Masson,
Bayoumi, and Samiei 1995; Edwards 1996; and Bailliu and Reisen 1998), for industrial-
country samples (Haque, Pesaran, and Sharma 1999), and for developing-country samples
(Corbo and Schmidt-Hebbel 1991; and Dayal-Ghulati and Thimann 1997).
The common feature of these papers is that they are based on reduced-form saving
equations, not necessarily derived from first principles. 4 They differ widely in other
dimensions, as they are based on different sample periods and countries as well as on
different model specifications and estimation techniques. Not surprisingly, only a few
saving determinants appear to be consistently significant across different studies and with
their estimated signs according to theory. They include the terms of trade, domestic and
foreign borrowing constraints, fiscal policy variables, and pension system variables.
Regarding other determinants for which consumption theories either differ regarding their
signs or point toward ambiguous signs, as in the case of income growth and interest rates,
these empirical studies differ widely. They also differ in reported significance levels of
variables for which theories tend to agree on expected signs, such as income level, inflation,
and demographic dependency ratios.
3. Empirical strategy
The above empirical studies capture a number of factors relevant to saving
decisions, but vary considerably in terms of data coverage and quality, empirical
specification and econometric procedure. Our primary objective here is to extend this
literature by providing a comprehensive characterization of the empirical association
between private saving rates and a broad range of potentially important saving determinants
using the best available data. To do this, we complement and extend previous work along
three dimensions. First, we use the largest set of consistent macroeconomic data on saving
assembled to date. Second, we adopt a reduced-form approach encompassing a variety of
saving determinants identified in the literature - rather than adhere to one particular narrow
structural model. Third, we employ a variety of estimation methods, but focus our attention
4
on estimators that attempt to control for heterogeneity and simultaneity, two problems that
likely plague most previous empirical studies.
3.1 The Data
Our basic data set draws from the saving database recently constructed at the World
Bank, and described in detail in Loayza, Lopez, Schmidt-Hebbel and Serven (1998a). To
our knowledge, such database represents the largest macroeconomic data set on saving and
related variables presently available. It comprises a maximum of 150 countries and spans
the years 1965-1994. The data have been subject to extensive consistency checks, and hence
they also represent an important improvement in terms of quality relative to other existing
data sets.5
The data set excludes the countries for which we found inconsistencies in basic
National Account, fiscal and financial data. These data limitations prevented the
construction of reliable saving measures, their disaggregation into public and private
saving, and/or the calculation of the inflation adjustments for the latter. For some of the key
variables in this paper, the effective data coverage in countries and years is therefore
limited. Nevertheless, for the "core" private saving regression, presented below, we
initially count with 1,254 complete observations spanning the years 1966-95.
From this initial sample, we decided to exclude the observations corresponding to
high inflation episodes. We base this decision on the fact that high inflation distorts
severely measured public and private saving (particularly the inflation-adjusted saving
measures).6 Moreover, in general high inflation renders National Account statistics largely
unreliable. For practical purposes, we set a threshold of +/- 50 percent annual inflation.
We apply the same threshold to the real interest rate, which in cases of high inflation is
mostly driven by inflation. For the "core" specification, these data adjustments lead to the
direct loss of 49 observations.7
In order to achieve a minimum time-series dimension, as well as to reserve
sufficient observations to implement our instrumental-variable estimators described below,
we limit our sample coverage to those countries with at least 5 consecutive annual
observations. After all these adjustments, the sample for our "core" specification consists of
1,148 observations. Since four observations per country must be selt aside for the
construction of instruments, the "core" regression sample consists of 872 observations for
69 countries - 20 industrial and 49 developing. As explained below, We also estimate
regressions for the national saving rate and for private saving rates derived frrom a narrower
definition of the public sector. For these regressions, the available sample comprises about
1,800 annual observations for 98 countries in the case of national saving rates and between
750-900 observations for 69countries in the case of private saving rates, depending on the
precise definition of the private and public sectors.8 This sample coverage exceeds that of
Edwards (1996), who considers 32 countries, and Masson, Bayoumi and Samici (1995),
whose sample includes 61 countries.
Finally, note that these panel data sets are heavily unbalanced, with the number of
time-series observations varying considerably across countries. The top panel of Table 1
5
provides information as to the composition of the "core" regression sample per decade and
development stage. Developing countries account for over half of the total number of
observations, and the 1980s are the decade most heavily represented in the data.
The precise definition of saving that we use also deserves comment. As in Loayza,
L6pez, Schmidt-Hebbel and Serven (1998b), for the nation as a whole our basic income
measure is gross national disposable income (GNDI), equal to GNP plus all net unrequited
transfers from abroad.9 Gross national saving is then defined as GNDI minus consumption
expenditure, with both measured at current prices.
In turn, for the private sector we implement four alternative measures of disposable
income and gross saving. These follow from the definition chosen for the public sector
(i.e., consolidated central government or broad public sector) and from whether the private
and public income and saving figures are adjusted or not for capital gains and losses due to
inflation. We respectively label the four alternatives that result as CU (unadjusted data
corresponding to the central government definition), CA (same as CU but after adjusting for
inflationary capital gains and losses), PU (unadjusted data corresponding to the public
sector definition of the govermnent), and PA (inflation-adjusted PU data). Notice that by
construction the CA and CU configurations lump local governments and public enterprises
together with the private sector. In turn, the PA and PU definitions of the public sector
correspond to either the general government or, when available, the consolidated non-
financial public sector, inclusive of public enterprises. Hence, of these four altematives, the
analytically preferable one is clearly PA. This is the private saving definition on which we
base our "core" regression and most of our experiments. In contrast, most empirical studies
use the more-readily available, but analytically problematic, CU measure.
In each case, gross private saving is computed as the difference between gross
national saving and the relevant definition of gross public saving. Gross private disposable
income (henceforth GPDI) is likewise measured as the difference between GNDI and gross
public disposable income, itself equal to the sum of public saving and public consumption.
Table 2 presents descriptive statistics and pairwise correlations for the five saving
ratios (national and the four alternative definitions of private saving). We report the full-
sample correlations as well as their cross-section counterparts. As expected, the correlations
are quite high in all cases (between 82 % and 97 %), with the correlations between the
national saving ratio and the private saving ratios being the lowest ones. The five saving
ratios also look very similar in their descriptive statistics (with a mean of about 20%, and
standard deviations of 8 %). The table also highlights the wide dispersion of private saving
ratios, which range from a minimum of-25 percent (Zambia 1985) to a maximum in excess
of 46 percent (Singapore 1984).
3.2 Empirical specification
We adopt an encompassing approach based on reduced-form linear equations. This
allows us to include a broad range of saving determinants. As dependent variables we use
both private and national saving ratios (to gross private and gross national disposable
income, respectively), although we concentrate on the former. We focus our attention on a
6
"core" set of regressors selected on the basis of analytical relevance (as well as data
availability); however, we also examine the empirical role of a number of less-standard
saving determinants.10
Following previous literature, our core regressors include a standard group of
income-related variables, namely the (log) level and the rate of growth of real per capita
disposable income, and the terms of trade. To ensure cross-country comparability of real
income figures, we convert the local-currency constant-price GNDI and GPDI data using
World Bank Atlas exchange rates averaged over 1965-94.
In addition, our basic regressors include both price and quantity financial variables.
The latter are the ratio of M2 to GNP, as standard indicator of financial depth, and the
domestic (in national saving regressions) or private (in private saving regressions) credit
flow relative to income, to capture consumers' access to borrowing."1 The price variable is
the real interest rate, defined as In[(1+i)1( + r)]. It is calculated using two alternative
measures of inflation: the current rate and the average of current and one-period-ahead
inflation. This yields two alternative real interest rate measures, of which our preferred one
is that using the averaged forward-backward inflation just described; however, we also
present empirical experiments using instead current inflation.
As conventional, we attempt to capture Ricardian effects in private saving equations
by including as regressor the public saving ratio, measured in a way consistent with the
definition of private saving under consideration; however, we also report somne experiments
adding the public investment / income ratio. In turn, demographic factors are represented by
the old and young-age dependency ratios as well as the proportion of urban population in
the total. Finally, we attempt to capture precautionary saving effects related to
macroeconomic uncertainty adding the inflation rate ln(l+±r,) among the regressors. In this
regard, we follow a rather voluminous literature in which the inflation rate has been used as
a proxy for price uncertainty (Deaton 1977) and, more generally, macroeconomic instability
(e.g., Fischer 1993).
We perfbrm additional empirical experiments using measures of trend and
temporary income and the terms of trade, as well as measures of incorne uncertainty,
constructed from our data. For this purpose, we use the time-series procedure introduced by
Maravall and Planas (1999). This procedure yields separate series for the trend and
temporary components of real income and the terms of trade. Combining the respective
trend and temporary components, we can construct one-step ahead forecasts of the original
variables. The dispersion of the corresponding one-step ahead forecast errors provides a
measure of the volatility of the respective innovations and hence the desired measure of
"uncertainty". As measure of dispersion we use the square of the forecast error.
Table 3 presents basic descriptive statistics and pairwise correlations (full-sample
and cross-section) on the private (PA) saving ratio and the core explanatory variables.
7
3.3 Econometric Issues
The estimation procedure needs to tackle three issues. First, rather than distort the
available information by phase averaging using an arbitrary phase length (e.g., computing 5
or 10-year averages), we choose to work with the original annual data in order to retain all
the information. This in turn means that we need to use a dynamic specification in order to
allow for inertia, very likely to be present in the annual information. Inertia in saving rates
can arise from lagged effects of the explanatory variables on saving. Thus, considering a
dynamic specification allows us to discriminate between short- and long-run effects on
saving.12 Second, some of the explanatory variables in the core specification above (e.g.,
the real interest rate, real income growth, etc.) are likely to be jointly determined with the
saving rate; therefore, we must allow and control for the joint endogeneity of the
explanatory variables. Third, we must also allow for the possible presence of unobserved
country-specific effects correlated with the regressors.
To address these issues, our empirical analysis is based on Generalized-Method-of-
Moments estimators applied to dynamic models using panel data. These estimators allow
us to control for unobserved country-specific effects and potential endogeneity of the
explanatory variables.13
Before we proceed, we must clarify the extent to which we control for joint
endogeneity. Our panel estimator controls for endogeneity by using "internal instruments,"
that is, instruments based on lagged values of the explanatory variables. Through this
method we can relax the assumption that the explanatory variables are strictly exogenous;
however, we cannot allow for full endogeneity of the explanatory variables. To be precise,
we must assume that the explanatory variables are "weakly exogenous," which means that
they can be affected by current and past realizations of the saving rate but must be
uncorrelated with future realizations of the error term. Conceptually, weak exogeneity does
not mean that future saving rates cannot be correlated with current realizations of variables
such as income growth or the interest rate (as would be predicted by most forward-looking
models). Rather, weak exogeneity means that future innovations (or unforeseen changes) to
the saving rate do not influence previous realizations of the saving determinants. We
believe that conceptually this assumption is not particularly restrictive; furthermore, we can
examine its validity statistically through several specification tests, as explained below.
The following is a brief presentation of our preferred methodology. Consider the
following dynamic reduced-form saving regression equation,
Sit =(SO +±O' X0 +± + (1)
where s is the saving rate, X represents a set of variables that potentially affect the saving
rate, rI represents a set of unobserved time-invariant country-specific effects, c is the error
term, and the subscripts i and t represent country and time period, respectively. 14
The usual method for dealing with the country-specific effect in the context of panel
data has been to first-difference the regression equation (Anderson and Hsiao 1982). In this
8
way the country-specific effect is directly eliminated from the estimation process. First-
differencing equation (1), we obtain,
sj - Si,,-, = a(si,, - t-2 ) + 0(X,, - Xi,,-,) + - (2)
The use of instruments is required to account for two facts. First, differencing the
saving regression introduces, by construction, a correlation between the differenced lagged
saving rate and the differenced error term. Second, some of the explanatory variables, X,
may be jointly endogenous with the saving rate. In particular, we would like to relax the
commonly held assumption that all explanatory variables are strictly exogenous (that is, that
they are uncorrelated with the error term, E, at all leads and lags). Relaxing this
assumption allows for the possibility of simultaneity and reverse causality, which are very
likely present in saving regressions. As explained above, we adopt the assumption of weak
exogeneity of the explanatory variables, in the sense that they are assumed to be
uncorrelated with future realizations of the error term (see Chamberlain. 1984). In this
presentation of the methodology, all variables are treated as weakly exogenous (with respect
to ). In practice, however, we treat some variables as strictly exogenous (again, with
respect to £ ); they are the young and old dependency ratios, the urbanization ratio, and the
terms of trade.
Under the assumptions that (a) the error term, e, is not serially corTelated, and (b)
the explanatory variables, X, are weakly exogenous, the following moment conditions apply
to the lagged saving rate and the set of explanatory variables,'5
ELsils(£-,,,-£it-1 )J= 0 for s > 2; t = 3,..., T (3)
E[X1 1 X .(£i i t-~1t)] = 0 fors>2;t=3,...,T (4)
We use a consistent GMM estimator based on these moment conditions, that we label the
difference estimator.
There are, however, conceptual and statistical shortcomings with this estimator.
Conceptually, we would like to study not only the time-series relationsh,ip between the
saving rate and its determinants but also their cross-country relationship, which is
eliminated in the case of the simple difference estimator. Statistically, Alonso-Borrego and
Arellano (1996) and Blundell and Bond (1997) show that when the explanatory variables
are persistent over time, lagged levels of these variables are weak instruments for the
regression equation in differences. The instruments' weakness has negative repercussions
on both the asymptotic efficiency and the small-sample bias of the difference estimator.'6
To confront these conceptual and statistical concerns, we use an alternative system
estimator that reduces the potential biases and imprecision associated with the usual
difference estimator (Arellano and Bover 1995, Blundell and Bond 1997). The alternative
estimator combines, in a system, the regression in differences with the regression in levels.
The instruments for the regression in differences are the same as above (i.e., the lagged
levels of the corresponding variable), so that, the moment conditions in equations (3) and
(4) apply to this first part of the system. For the second part of the system, the regression in
9
levels, the instruments are given by the lagged differences of the corresponding variables.
These are appropriate instruments under the following additional assumption: although
there may be correlation between the levels of the right-hand side variables and the country-
specific effect in equation (1), there is no correlation between the differences of these
variables and the country-specific effect. This assumption results from the following
stationarity property,
E[s,.1+p .rE]= E[s11±q .1] for all p and q (5)
E[X't+P 77j]= E[Xi,+q .'] for all p and q (6)
Therefore, the additional moment conditions17 for the second part of the system (the
regression in levels) are given by the following equations18:
E[(si- t-l-Si-2 H)* (i + 8 ,t )] = 0 (7)
E[(Xi,t - Xi't-l ) * (77 i + e iat )] = ° (8)
We use the moment conditions presented in the above equations, and, following
Arellano and Bond (1991) and Arellano and Bover (1995), we employ a Generalized
Method of Moments (GMM) procedure19 to generate consistent estimates of the
parameters of interest.
The consistency of the GMM estimator depends on whether lagged values of the
explanatory variables are valid instruments in the saving regression.20 To address this issue
we consider three specification tests suggested by Arellano and Bond (1991), Arellano and
Bover (1995), and Blundell and Bond (1997). The first is a Sargan test of over-identifying
restrictions, which tests the overall validity of the instruments by analyzing the sample
analog of the moment conditions used in the estimation process. Failure to reject the null
hypothesis gives support to the model. The second test is the "difference-Sargan" test,
which examines the null hypothesis that the lagged differences of the explanatory variables
are uncorrelated with the residuals (which are the additional restrictions imposed in the
system estimator with respect to the difference estimator).21 The third test examines the
hypothesis that the error term Eit is not serially correlated or, if it is correlated, that it
follows a finite-order moving average process. We test whether the differenced error term
(that is, the residual of the regression in differences) is first-, second-, and third-order
serially correlated. First-order serial correlation of the differenced error term is expected
even if the original error term (in levels) is uncorrelated, unless the latter follows a random
walk. Second-order serial correlation of the differenced residual indicates that the original
error term is serially correlated and follows a moving average process at least of order one.
If the test fails to reject the null hypothesis of absence of second-order serial correlation, we
conclude that the original error-term is serially uncorrelated and use the corresponding
moment conditions.22
Measurement error. The discussion above has abstracted from issues regarding
measurement error. It is likely, however, that most variables in our econometric model
suffer from measurement error. Given that our model is dynamic, not only errors in the
explanatory variables will cause biased estimation but also errors in the saving rate, the
10
dependent variable. We can deal with measurement error through our instrumental variable
procedure. We allow for measurement error of two kinds. The first type is mostly constant
over time but specific to each country. We group this type of error with the unobserved
country specific effect and control for it accordingly. The second type of measurement
error we allow for is the standard random error. If this is serially uncorrelated, it can be
shown that the same lag structure for the instruments that control for endogeneity also deals
with measurement error. If the random measurement error follows a rnoving average
process of order 1, then we need to use instruments lagged one more period than what
would be necessary if there were no measurement error (or if it were seriall-y uncorrelated).
In practice for all private saving rate regressions, we take the conservative approach of
allowing for measurement error that follows an MA(l) process (see footnote 22). The
specification tests for the validity of the instruments can also be used to assess whether the
control for measurement error is appropriate.
4. Estimation results
We now present the estimation results for private and national saving rates. In each
case, we organize our discussion around the core empirical specification introduced above.
As noted earlier, the core regressors are the same for private and national saving rate
regressions except for the fact that government saving is included only in private saving
equations. We focus on the private saving rate, and concentrate on the private saving
measure that is most analytically sound. This is the measure that corresponds to the public
sector defined broadly to include regional and local governments and, where possible,
public enterprises, and adjusting for capital gains and losses due to inflation.
In order to test the robustness of the basic results and to enlighten their
interpretation, we also conduct experiments along four dimensions. First, we employ
alternative econometric techniques. Second, we use alternative samples: we break the
world sample into OECD and developing-country subsamples, and we also present a world
sample that excludes potential outliers. Third, we work with alternative definitions of
private saving. And, fourth, we explore the importance of additional explanatory variables.
Finally, we consider national saving regression results obtained under various econometric
techniques.
Before proceeding to the detailed discussion of the results in Tables 4-8, we note
that the specification tests generally support our GMM-IV panel estimates. I[n all cases, the
Sargan test of overidentifying restrictions cannot reject the null hypothesis that the
instruments are uncorrelated with the error term. Likewise, the tests of serial correlation
reject the hypothesis that the error term is third-order serially correlated (and, in most cases,
that it is second-order serially correlated), giving additional support to the use of
appropriate lags of the explanatory variables as instruments for the estimation. For the core
regression (Table 4, column 6), we also conduct the Sargan-difference test, which as
explained above tests the validity of the additional restrictions imposed by the system
estimator relative to the difference estimator. In agreement with the conclusions of the
other two specification tests, the Sargan-difference test does not reject the additional
restrictions of the system estimator (p-value 0.59).
I1
Prior to presenting the results, we must clarify their interpretation. Our econometric
methodology is designed to isolate the effect of the exogenous component of each
explanatory variable on the saving rate. To the extent that our assumptions regarding the
instruments employed in the GMM procedures are correct, we succeed in isolating the
effects going from the explanatory variables to the saving rate. The specification tests
presented above support the validity of our instruments and, thus, allow us to draw
inferences regarding the link between the exogenous component of policy and non-policy
variables and saving rates. In the following, when we mention the effect of a given variable
on the private saving rate, we are referring to the association between the exogenous
component of that variable and the saving rate.
4.1 Basic results
Table 4 reports the results of the private saving rate regression using alternative
estimators on the full sample and employing the core specification. While there are a
number of similarities among the various estimates, as explained in the previous section our
preferred estimation method uses the GMM system estimator. Hence we first discuss the
results obtained with this estimator (column 6) and then compare them with those obtained
with alternative estimation methods.
Persistence. The lagged private saving rate has a positive and significant
coefficient, whose size (0.59) reveals a large degree of persistence. This, in turn, implies
that the long-run effects of other private saving determinants are more than twice (2.44
times, to be exact) as large as their respective short-run effects -- if all changes in these
variables were permanent.
Income. Both the (log) level and the growth rate of real per capita private
disposable income have a positive and significant effect on the private saving rate --as
private agents become richer or their incomes grow faster, their saving rate increases.
According to the estimated coefficients, an increase in income by 10 percent raises the
private saving rate by 0.47 percentage points on impact. In turn, the estimated growth
coefficient indicates that an increase in the income growth rate by 1 percentage point leads
to a private saving rate increase of 0.45 percentage points in the short run. Lastly, a 10
percent improvement in the terms of trade increases the private saving rate by 0.74
percentage points in the short run.
In our basic regression specification, we estimate the effect of changes in income
levels and growth rates and in the terms of trade; however, we cannot tell whether the
estimated effects are due to permanent or temporary changes in these variables. We return
to this issue below, when we attempt a decomposition of these variables into their
permanent and temporary elements. In so far as the estimated coefficients represent the
saving effects of temporary changes in income levels and growth rates, their positive sign is
consistent with standard intertemporal consumption theories. If they represent the effect of
permanent changes in income levels and growth rates, their positive sign must be explained
resorting to more recent theoretical developments. Thus, the positive income level effect
would be consistent with models of subsistence consumption, while the positive income
12
growth effect could be explained by a model featuring consumption habits or the life-cycle
model where income growth accrues mostly across cohorts.
On the whole, the significant effects of income levels and growth rates imply that
policies that spur development are an indirect but most effective way to raise saving. To
the extent that a. significant fraction of the increased saving is channeled into productive
domestic investment in many countries (as suggested by the evidence in support of the co-
movement of saving and investmnent first underscored by Feldstein and lHorioka ,1980),
successful growth policies may be able to set in motion a virtuous cycle of saving, capital
accumulation, and growth.
Financial variables. The real interest rate has a negative impact on the private
saving rate, suggesting that its income effect outweighs the sum of its substitution and
humnan-wealth effects. A 1 percentage point increase in the real interest rate produces a
private saving rate decline of about 0.25 percentage points in the short run. This result
should be taken with some caution, however, in view of the strong negative correlation
between inflation and the real interest rate (Table 3), which suggests that our real interest
rate measure may reflect more the action of nominal interest rate controls and financial
repression than consumers' intertemporal rate of substitution. In turn, our indicator of
financial depth (M2/GNP) has a small and statistically insignificant impactl on the private
saving rate. Other experiments using instead credit ratios to measure financial depth led to
similar results. Finally, the flow of private domestic credit relative to income carries a
negative and significant coefficient, suggesting that the relaxation of credit constraints leads
to decrease in the private saving rate (in agreement with evidence given by Jappelli and
Pagano 1995). When the flow of private credit rises by 1 percent of income, the private
saving rate decreases by 0.32 percentage points on impact.
These results provide a bleaker view of the saving effects of financial liberalization
than suggested by previous studies, in both the price and quantity dimensions: both higher
interest rates and larger private domestic credit flows exert a negative effect on private
saving rates. Although on the whole we do not find any positive, direct effects of financial
liberalization on saving rates, there is considerable evidence that financial reforn has a
positive impact on growth (e.g., Levine, Loayza and Beck 2000) and, through this channel,
a potentially important indirect effect on saving rates.
Fiscal policy. A rise in the public saving ratio leads to a statistically significant
decline in the private saving rate. Specifically, the private sector reduces its saving rate by
0.29 percentage points for each 1 percentage point increase in the public saving ratio within
the same year the policy change occurs. Over the long term, however, the offset coefficient
rises to 0.69. Therefore a permanent rise in public saving by 4% of GNDI will raise national
saving by 2.8% of GNDI within a year, but only by some 1.2% of GNDI in the long tern.
The former result is at the low end of previous estimates, while the latter is alt the upper end,
so that allowing for inertia in saving helps reconcile some conflicting estimates found in the
literature (see Lopez, Schmidt-Hebbel and Serven 2000). While our point estimates fall
short of unity, a Wald test of the null of fall long-run Ricardian offsetting yields a p-value
of .10, which provides some evidence against the Ricardian hypothesis but -fails to reject it
at conventional significance levels.
13
Demographic variables. All three demographic variables under consideration,
namely, the urbanization ratio and the young and old dependency ratios, have a significantly
negative impact on the private saving rate. The negative effect of the urbanization ratio can
be explained along the precautionary-saving motive -- lacking the means to diversify away
the high uncertainty of their mostly agricultural income, rural residents tend to save a larger
proportion of their income. The negative coefficients on the dependency ratios are
consistent with standard life-cycle models of consumption. The null of equality of estimated
coefficients is rejected -- the coefficient on the old dependency ratio is significantly larger
than that on the young dependency ratio. This likely reflects the fact that the labor force
effectively includes a non-negligible proportion of the population aged under 16 (the cutoff
point for the young dependency ratio) in many countries.
Both urbanization and the old-age dependency ratio are strongly positively
correlated with per capita income (Table 3), so that they contribute to dampen the positive
effect of rising incomes on saving noted above. In turn, the negative saving effect of young-
age dependency suggests that developing countries with young populations that aim at
accelerating their demographic transition and speed up the decline in young-age dependency
ratios, may witness a transitory increase in their saving ratios before reaching the next stage
of demographic maturity. At this stage old-age dependency rises swiftly --and saving rates
level off again.
Macroeconomic uncertainty. Like in much of the recent growth literature, in the
core specification our proxy for macroeconomic uncertainty is the inflation rate. We find
that a rise in inflation has a positive coefficient: a reduction of inflation by 10 percentage
points reduces the private saving by over 1 percentage point through this channel. This
suggests that increased macro uncertainty (regarding for example nominal incomes, future
policies and so on) induces people to save a larger fraction of their income for precautionary
motives.23 While one might be tempted to conclude that inflation stabilization could have
an adverse effect on saving, it is important to keep in mind that stabilization also affects
saving through other indirect channels that are likely to more than compensate for any
negative direct effect of inflation. In this regard, there is systematic evidence that lower
inflation raises growth (see Fischer 1993, Andres and Hernando 1997, among many other
studies) and, as discussed below, the latter has a major positive effect on private saving.
Further, the fiscal-adjustment component of macroeconomic stabilization also has an
unambiguously positive effect on national saving, as noted above.
4.2 Alternative Estimators
Table 4 also presents results obtained with alternative estimation techniques. The
first two columns present static OLS estimates, using respectively the cross-section data
(i.e., country averages) and the pooled annual data. Both specifications are often
encountered in saving studies. The third column adds the lagged dependent variable to the
second. It is important to keep in mind, however, that in all three cases OLS is likely biased
and inconsistent because it ignores unobserved country-specific effects and joint
endogeneity of the explanatory variables. In the fourth column, the Within estimator is
used to control for country-specific effects, but still ignoring joint endogeneity. An
14
additional problem already noted earlier is that the presence of a lagged dependent variable
renders the within estimator inconsistent in short panels, although its fate in a heavily
unbalanced panel such as ours is somewhat less clear. The fifth column presents the results
obtained with the GMM estimator based on a regression in differences which, as explained
earlier, deals with country-specific effects and joint endogeneity. However, the GMM
difference estimator eliminates the cross-country variation of the data (like the Within
estimator) and may suffer from small-sample bias due to the use of weak instruments. By
contrast, the system GMM estimator in column 6 makes use of both cross-country and time-
series information.
In many cases, the results obtained with our preferred estimation technique, the
GMM system estimator, are qualitatively similar to those obtained with the alternative
estimators shown in Table 4. All estimators yield positive effects of the (log) level and
growth rate of real income and negative effects of public saving and the old dependency
ratio - although the coefficients vary in size and statistical significance. Likewise, in all
cases (with the obvious exception of the static OLS estimates) we find significant evidence
of private saving inertia, although likely exaggerated in the pooled OLS estimates due to
their lack of control for country-specific effects.
There are., however, some notable exceptions. For example, the use of time series
information (columns 2-6) reverses the parameter signs of the terms of trade and credit
flows relative to those found in the cross-section OLS estimates. By contrast, cross-section
information (columns 1-3 and 6) is needed to obtain a significant negative effect of the
urbanization ratio. In turn, controlling for country-specific effects (columns 4-6) reverses
the sign of the M2/GDP ratio from positive to negative. In this regard, however, notice that
M2/GNP is likely to be a better proxy for financial depth in the cross-section dimension
than in the annual time-series dimension, where it may reflect mostly other short-term
factors like monetary policy. Finally, the sign and significance of the coefficients of the
inflation rate and the interest rate do not show a clear pattern across alternative estimators.
4.3 Alternative samples
In Table 5, we present the GMM system estimates for alternative samples of
countries, namely, the sample of less-developed countries (LDC) and the sample of
industrial countries (OECD), in addition to the full-sample estimates already described. We
also present estimates for a sample that excludes outliers without resorting to bounds on
inflation. We obtain this sample by restricting the observations of each variable in the core
specification to lie between 4 standard deviations from the respective mean. The estimated
results for the restricted sample are quite similar to those obtained with the full sample
(which, as explained above, imposes a 50% bound on inflation). We take this similarity as
evidence that our core regression results are not driven by outlier observations and that the
inflation bound is not distorting the estimation results.
Qualitatively, the estimates obtained on the subsamples of developing and industrial
countries are broadly similar to their full-sample counterparts, but there are two important
exceptions. First, surprisingly, the coefficient on the real interest rate is not significant for
either the OECD or LDC samples, while it was significantly negative in the full sample.
15
This again raises the suspicion that the accuracy with which real interest rates measure
intertemporal prices varies across the two subsamples.24 Likewise, M2/GNP is the other
variable whose sign is not robust across samples: negative and insignificant in the full
sample, positive and insignificant in the LDC sample, and significantly positive in the
OECD sample.
There are also some changes in the magnitude of the estimated coefficients across
samples. The level of private income and its rate of growth are always positively related to
the private saving rate, but their estimated coefficients are smaller in the OECD (where the
level effect is in fact insignificant, a pattern already found by Modigliani 1992) than in the
LDC sample. This seems consistent with subsistence-consumption theories, which predict
a higher impact of income and growth on saving rates at low levels of income. The size of
the estimated coefficients of the demographic variables is uniformly smaller in the case of
the OECD sample than in the LDC and full samples. This result likely reflects non-linear
saving effects of the demographic variables, as well as the greater homogeneity across
OECD populations in terms of urbanization and age structure. The private credit flow ratio
also carries a considerably larger coefficient in the LDC subsample than in the OECD
subsample. This is possibly due to the fact that credit constraints in developed countries are
mostly non-binding, and therefore increases in private credit flows in these countries do not
reflect improved credit availability.
Finally, it is puzzling that the coefficient on the public saving rate is found to be
larger in the group of developing countries than in the OECD subsample. We would expect
that the conditions for Ricardian equivalence to hold are more prevalent in industrial than in
developing countries. The large estimated coefficient on the public saving ratio for the
group of LDCs may reveal that, despite our best efforts, measurement error is partly driving
the negative correlation between private and public saving rates. This is a likely possibility
given that private saving was derived as the difference between national and public saving -
-any error in public saving would translate mechanically in an error of the opposite sign in
private saving. If we assume the estimated public saving coefficient for the OECD sample
as mostly free from measurement error, then we find a larger effect of public saving on
national saving than reported above. A permanent increase in public saving of 4% of GNDI
would lead to an increase in national saving of 3.6% of GNDI in the short run and 2.6% of
GNDI in the long run. Interestingly, for both the industrial and developing country
subsamples, Wald tests allow clear rejection of full long-run Ricardian offsetting, with p-
values below I percent.
4.4 Alternative definitions of the public sector
Table 6 presents full-sample system-GMM estimation results using the four
alternative definitions of the public sector introduced earlier. Up to now we have focused on
the public sector definition that includes the general government and, when available,
public enterprises; furthermore, the related saving and income data have been adjusted to
account for the inflationary erosion of privately-held public liabilities. The results of this
core regression, discussed above, are reproduced in Table 6, column 4, under the heading of
"PA." The other columns make use instead of the three alternative public- (and private-)
sector saving measures introduced earlier corresponding to, respectively, unadjusted central
16
government (CU, column 1), adjusted central government (CA, column 2), and unadjusted
consolidated public sector (PU, colurn 3). 25 Performing this robustness check for
alternative public-sector measures is important given that differences in empirical results
across different studies have often been attributed to differences in public sector definition.
Surprising to us, the estimated results are remarkably robust across definitions of the
public sector. Concerning the adjusted and unadjusted data, this is not all that striking
given that we have dropped from the sample the observations corresponding to extreme
inflation episodes. In any case, Table 6 shows only one exception that deserves
discussion.26 The estimated coefficient on public saving is larger in the central government
regressions than in those corresponding to the consolidated public sector. In fact, the
"offset" coefficient is about 25% larger in the case of the central government, so that in the
long run it reaches 72% and 95% in the CU and CA specifications, respectively, in contrast
with the 58% and 69% that results from the PU and PA estimates. The straightforward
explanation of this result is that there is a larger degree of offset between the central
government and other public-sector levels (provincial and state governments and public
enterprises) thain between the consolidated public sector and the private sector. This in turn
implies that studies of Ricardian equivalence based on a central-government definition of
the public sector tend to overstate the public-private saving offset.
4.5 Additional explanatory variables
In Table 7, we add other potential private saving determinants, excluded from the
'core" set of explanatory variables because they are either less commonly used in the
literature or not well justified conceptually. We consider each variable inl turn. The first
one is the current account deficit (relative to private disposable income). While popular in
the literature, the current account deficit is a somewhat dubious regressor, as it is jointly
determined with saving in countries and/or at time periods characterized by unrestricted
access to net foreign lending, and is exogenously determined otherwise. Thus, it is difficult
to interpret the results obtained with this variable when using samples that combine
observations on the two regimes (like ours and most others). In our case, we try to correct
at least in part for these problems by treating the current account ratio as an endogenous
variable in our GMM-IV procedure. The resulting estimates show that an increase in
external saving (i.e., a worsening of the current account deficit) is partly offset by a decline
of private saving; the offset coefficient is on the order of 33% in the short run, and about
60% in the long run. At face value, the implication is that an increase by, say, 2% of GNDI
in the exogenous component of foreign lending reduces private saving by approximately
1.2% of GNDI in the long run. With the important caveat just noted, this agrees with the
standard view that external saving acts as a substitute rather than as a complement to
domestic private saving. The remaining coefficients show little change, although that on
income growth becomes smaller in size.
The second variable is the ratio ofpublic investment to private disposable income. If
public investment is perceived to be just like public consumption, its estirmated coefficient
would be of equal magnitude but opposite sign as that for the public saving ratio. If it is
viewed as productive investment, its coefficient would be zero. What we obtain, however,
is a significantly negative coefficient. This suggests a somewhat puzzling complementarity
17
between public and private goods, in the sense that an increase in government investment
leads to an increase in private consumption. As before, the rest of the parameter estimates
show little variation.
The third variable is the proxy for income uncertainty mentioned earlier, constructed
as the standard error of the one-period-ahead forecast error from a univariate time-series
model for income based on Maravall and Planas (1999).27 Although its estimated
coefficient has the positive sign expected from the precautionary saving motive, it is not
statistically significant, likely reflecting the rudimentary nature of our constructed proxy.
Fourth, we consider the effect of the oil shocks on private saving by including dummy
variables for the years 1973, 1974, 1979, and 1980. Although the estimated coefficients for
the four years are found to be negative (reflecting the predominance of oil importers in our
sample), only those for the years 1973 and 1974 are significantly so;28 the remaining
coefficients are mostly unchanged. This result indicates that for the typical (oil-importing)
country the temporary income loss due to a rise in oil prices leads to a decrease in saving
rather than a downward adjustment of consumption.
Next, in columns 5 and 6 we analyze the effects of the perrnanent and temporary
components of, respectively, private disposable income and the terms of trade. Note that
the decomposition procedure causes the loss of some observations, which are used to
estimate the underlying univariate models. Remarkably, in both cases we find that the size
of the coefficient on the temporary component is much larger than that of the permanent
component (although the latter maintains a positive sign). In the case of income, neither
coefficient is significant, while both are in the case of the terms of trade.29 a The larger
impact on the saving rate of temporary income is consistent with consumption smoothing
by forward-looking agents. In turn, the fact that the permanent component of the terms of
trade retains a significant positive coefficient (although much smaller than that on the
temporary component) might reflect the lack of access to external borrowing that many
developing countries suffered during much of our sample period.
Finally, in column 7 we reexamine the effect of the real interest rate on saving by
using in its calculation the current inflation rate, rather than the average of the current and
next-year inflation rates, as done up to now. The sign and significance of the real interest
rate coefficient remain as before, though its magnitude is larger. The remaining parameters
are mostly unaffected, but the inflation rate now adopts a negative, though insignificant,
coefficient, reflecting the strong correlation (-0.70) between the ex-post real interest rate
and the inflation rate. This suggests that the larger coefficient on the former variable may be
capturing in part the positive effect of inflation on the private saving rate found earlier.
4.6 National saving rate
Table 8 presents the full-sample results for national saving rate regressions obtained
with alternative estimators. The table is analogous to Table 4, on the private saving rate,
except for the fact that in the national saving rate regressions we do not include the public
saving ratio as an explanatory variable. The maintained assumption in the national saving
rate regressions is that the public saving rate is driven by the same determinants as the
private saving rate (excluding public saving itself, of course). In spite of the much larger
18
data samples used here, close comparison between these results and those obtained with the
private saving rate reveals a remarkable similarity in terms of sign and significance of the
estimated coefficients. Indeed, our preferred (GMM-system) estimates azre basically the
same for the private and national saving rates, with three differences of some relevance.
First, the real interest rate still carries a negative coefficient, but it is not significant in the
national saving rate regressions; second, the effect of the level of income is much larger in
the case of the national saving rate; and third, the degree of persistence is lower for national
than for private saving rates. In turn, the results obtained using alternative estimators are
also quite similar for both dependent variables. We take this broad similarity, along with the
fact that the theoretical literature provides a framework for the analysis of private saving
decisions, as supportive of our choice to concentrate on the empirical determinants of the
private saving rate.
5. Concluding Remarks
Private and national saving rates display very large variation across countries and
over time. This paper has explored empirically the roles of policy variables and other
factors in these large saving disparities. The paper extends the literature in several
dimensions. First, it makes use of a new data set on saving and related macroeconomic
variables, whose coverage in terms of countries and years is considerably broader than those
used in previous literature. Second, it explores different dimensions of saving -- of the
private sector and the nation. Third, it tries to correct for issues such as simultaneity and
unobserved country-specific effects, making use of instrumental variable estimators based
on "internal" instruments. Fourth, it performs extensive robustness checks to changes in
estimation procedures, country samples, private-saving measures, and empirical
specifications.
The main empirical findings reported in the paper are the following:
- Private saving rates show inertia, that is, they are highly serially correlated even
after controlling for other relevant factors. The effects of a change ina a given saving
determinant are thus fully realized only after a number of years., with long run
responses estimated to be more than two times larger than short-run (within a year)
ones.
* Private saving rates rise with the level and growth rate of real per capita income.
The influjence of income is larger in developing than in developed countries. In
developing countries a doubling of income per capita is estimated, other things
equal, to raise the long-run private saving rate by some 10 percentage points of
disposable income. Likewise, a 1 percentage-point rise in the growth rate raises the
private saving rate by a similar amount. The overall implication is that policies that
spur development are an indirect but effective way to raise private saving rates.
* The predictions of the life-cycle hypothesis are supported in that dependency ratios
have a negative effect on private saving rates. The negative impact of an increase in
the old-dependency ratio is more than twice as large as that of the young-
dependency ratio.
19
* The precautionary motive for saving is supported by the finding that inflation -
conventionally taken as a summary measure of macroeconomic volatility - has a
positive impact on private saving, holding other factors constant.
* Fiscal policy is a moderately effective tool to raise national saving. An increase in
public saving by, say, 4% of GNDI will raise national saving by 2.8% of GNDI
within a year, but only by some 1.2% of GNDI in the long term. The evidence points
against full Ricardian equivalence.
* The direct effects of financial liberalization are largely detrimental to private saving
rates. First, enhanced credit availability reduces the private saving rate. Second,
larger financial depth does not raise saving, and nor do higher real interest rates.
These results are, in general, robust to the use of alternative saving definitions,
regression specifications, and data subsamples.
lIn a companion paper, L6pez, Loayza, Schmidt-Hebbel and Serven (1998b) provide a detailed description of
the basic data set, including descriptive statistics and stylized facts.
2 We note from the outset that these equations are anchored in private consumption (or saving) theory. When
applying the model to national saving measures we implicitly assume that public saving is determined by the
variables that drive private saving. We, thus, abstract from a separate behavioral framework for public-sector
saving. This is consistent with both the standard practice of empirical studies for aggregate (national) saving
and the lack of an established theory of public saving.
3 A detailed discussion of expected signs of saving determinants in Table 1 and how they relate to specific
consumption theories is in Loayza, Lopez, Schmidt-Hebbel and Serven (1998b). Further reviews of
consumption hypotheses and their relation to empirical findings can be found in Schmidt-Hebbel and Serven
(1997, 1999).
4L Like in other areas of empirical work, consumption studies face a steep trade-off in the choice between
closed-form solutions rigorously derived from (typically narrow) consumption optimization models, and
atheoretical specifications encompassing a large number of consumption determinants. In line with the
objectives of this paper, here we limit our attention to international studies using panel data and based on the
latter approach.
5 Full details on data sources are given in the companion paper by Loayza et al. (1998a).
6 The reason is that minor changes in the computation method (e.g., regarding the time within each year at
which prices and public debt are measured) can result in huge changes in the adjusted saving measures.
7 As robustness check, we worked with an alternative bound of 75% annual inflation. This reduces the number
of observations discarded (14 instead of 49) and leads to estimates very similar to those reported in the paper,
but at the cost of reduced precision. A second robustness check (presented in the section on "alternative
samples" in the main text) consisted of restricting the sample so that the data points for each variable lie
between 4 standard deviations from the respective mean. The corresponding estimation results are quite
similar to those obtained with the 50% inflation bound. In turn, raising the threshold for each variable to 5
standard deviations leads to estimates and precision analogous to those obtained with the 75% inflation bound.
8 In some variants of the basic specification, actual sample sizes are smaller (as reported in at the bottom of
Tables 4-8 below) due to the more limited data availability on some of the 'additional' regressors.
9 Qualitatively, this departs from convention by adding together current and capital transfers from abroad
(typically, only the former are included in saving measures) -- a decision guided by the fact that they are not
separately available until the late 1970s. Quantitatively, however, this makes little difference because in the
light of the available data capital transfers from abroad appear insignificant for virtually every country and
year, with the only exception of 17 observations, most of them from small-island economies that are anyway
20
excluded form the samples used in this paper. See Loayza, L6pez, Schmidt-Hebbel and Serven (1998a) for
more details.
10 The limited availability of good-quality annual informnation across countries on pension systems and
measures of income inequality prevents us from including these variables in our core specification.
11 Since stocks are typically measured at the end of the year, we compute our ratios to income using the
average of the current and previous year stocks (the latter having being brought to current year prices). Flows
are in tum obtained as differences of stocks for two consecutive years.
12 While seldom considered in empirical studies, saving inertia can arise directly from consumption habits and
even from consumption smoothing. For example, with a quadratic utility function a la Hall (1978), if income
follows an AR(1) process then saving will also be AR(1). In our sample, the first-order autocorrelation
coefficient of the private saving rate is 0.88.
13 The Generalized Method of Moments (GMM) estimator was proposed by Chamberlain (1984), Holtz-
Eakin, Newey and Rosen (1988), Arellano and Bond (1991), and Arellano and Bover (1995), and has been
applied to cross-country studies by, among others, Caselli, Esquivel and Lefort (1996), Easterly, Loayza and
Montiel (1997), and Fajnzylber, Lederman, and Loayza (1998). For a concise presentation of the GMM
estimator, see chapter 8 of Baltagi (1995).
14 Time dunmmies can also be included in equation (1) to account for time-specific effects.
15 The assumption that the error tern is not serially correlated can be relaxed and replaced by the assumption
that it follows a finite-order moving average process. In this case, the moment conditions must be modified
accordingly. For example, if £ is MA(1) (as it appears to be in some of our private saving regressions below)
the moment conditions in equations (3) and (4) must be replaced by,
E[st-s (E 1-tl)] 0 for s>3; t=3,...,T (3')
E[X1-1 (8't -s,j)]=0 for s>3; t=3,...,T (4')
16 As the variables' persistence increases, the asymptotic variance of the coefficients obtained with the
difference estimator rises (that is, the asymptotic precision of this estimator deteriorates). Furthermore, Monte
Carlo experiments show that the weakness of the instruments produces biased coefficients in small samples.
This bias rises with the variables' over-time persistence and the importance of the country-specific effect and
declines with the size of the time-series dimension. An additional problem with the simple difference
estimator relates to measurement error, namely, differencing may exacerbate the bias due to errors in variables
by decreasing the signal-to-noise ratio (see Griliches and Hausman, 1986).
17 Given that lagged levels are used as instruments in the differences specification, only the most recent
difference is used as instrument in the levels specification. Using other lagged differences would result in
redundant moment conditions (see Arellano and Bover 1995).
18 Equations (7) and (8) give the appropriate moment conditions when the error term, £, is serially
uncorrelated. If, however, the error term follows a moving average process of order 1, then the appropriate
differences to be used as instruments must be lagged one more period.
'9 We are grateful to Stephen Bond for providing us with a computer program (DPD version 8/8/96) to apply
his and Arellano's estimator to an unbalanced panel data set.
20 In this paper the moment conditions are applied such that each of them corresponds to all available periods,
as opposed to each moment condition corresponding to a particular time period. In the former case the
number of moment conditions is independent of the number of time periods, whereas in the latter case, it
increases more than proportionally to the number of time periods. Most of the literature dealing with GMM
estimators applied to dynamic models of panel data treats the moment conditions as applying to a particular
time period. This approach is advocated on the grounds that it allows for a more flexible variance-covariance
structure of the moment conditions (see Ahn and Schmidt 1995); such flexibility is achieved without placing a
serious limitation on the degrees of freedom required for estimation of the variance-covariance matrix because
the panels commonly used in the literature have both a large number of cross-sectional units and a small
number of time-series periods (typically not more than five). We have, however, chosen to work with the
more restricted application of the moment conditions (each of them corresponding to all available time
periods) because of a special characteristic of our panel, namely, its large time-series dimension (well in
excess of the time dimension usually encountered in micro panels). This approach allows us to work with a
manageable number of moment conditions, in a way such that the second-step estimates, which rely on
estimation of the variance-covariance matrix of the moment conditions, do not suffer from over-fitting biases
(see Altonji and Se,al 1994, and Ziliak 1997).
21
21 Both the Sargan statistic and the "difference" Sargan statistic are asymptotically distributed as Chi-square
under the null hypothesis of validity of their respective instruments. The number of degrees of freedom of the
Sargan test is equal to the number of overidentifying restrictions of the system estimator. The number of
degrees of freedom of the "difference" Sargan test is given by the number of additional restrictions in the
system estimator with respect to the difference estimator, that is, the difference between the number of
overidentifying restrictions of the system estimator and that of the difference estimator.
22 However, if the test rejects the null hypothesis of no second-order serial correlation but fails to reject the
null of absence of third-order serial correlation, we conclude that the original error term is MA(1) and,
therefore, use the moment conditions appropriate to this case. As shown below, in the private saving
regressions we find in some cases evidence that the error term is MA(I) and, in others, that it is serially
uncorrelated; for purposes of comparability across regressions we adopt the conservative strategy of choosing
the instrument sets for the regressions as if the error term were always MA(l ). In the case of national saving,
we fmd that the error term can be well characterized as serially uncorrelated, and we choose the instrument set
accordingly.
23 Deaton (1977) finds the same result but proposes a somewhat different explanation: to the extent that the
increase in inflation is unanticipated, a larger saving rate may result from confusing the increase in the overall
price level with a rise in the relative prices of certain goods.
24 It seems plausible that measured real interest rates are more closely related to intertemporal decisions in the
industrial countries (where the sample mean of the real interest rate is positive) than in developing countries
(where it is negative).
25 The sources of central government data are different from those of public sector data. The former cover
many more countries but fewer years (from 1970 on only). For comparability, all the regressions in the table
use the same set of countries, and hence the central government-based saving regressions possess fewer
observations.
26 The second exception is that M2/GNP has a positive and significant coefficient only in the regressions
corresponding to the central government definition of the public sector.
27 Using instead the variance of the forecast error to measure uncertainty yielded similar results.
28 Other year dummies, when added to the regressions, were likewise insignificant.
29 Other experiments using instead the Hodrick-Prescott decomposition yielded qualitatively similar results:
larger coefficients on the temporary than on the pernanent components of both variables (the latter was in fact
negative for the terms of trade), but in this case all significantly different from zero.
22
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25
Table 1: Determinants of the Private Saving Ratio to Income in Previous Panel Studies
Variable Category Specific Variable Expected Sign Empirical Findings
Income Income level: actual 0 or + + (1, 2, 3, 4) 0 (5, 6)
Temporary / permanent + / 0 or +
Terms of trade: actual 0 or + + (2, 4, 6)
Temporary / permanent + I 0 or +
Growth rate: actual Ambiguous + (2, 3) 0 (4, 5, 6)
Rates of return Interest rate Ambiguous 0 (1, 3, 5, 6) + (2)
Uncertainty Variance of innovations to +
saving determinants
Inflation or other measures of + - (4) 0 (1, 2, 3, 6)
macro instability
Measures of political instability +
Domestic borrowing Private credit flows - + (3)
constraints Broad money flows
Income
Foreign borrowing Foreign lending
constraints Current account deficit - - (1, 2, 3)
Financial depth Private or domestic credit Ambiguous - (5)
stocks Ambiguous + (1, 3, 4)
Money stocks
Fiscal policy Public saving - (1, 3)
Public surplus - (2, 5, 6) 0 (4)
Public consumption Ambiguous - (2, 6)
Pension system Pay-as-you-go pension 0 or- - (3, 4, 5)
transfers to old
Mandatory fully-funded 0 or + + (4)
pension system contributions
Fully funded pension assets Ambiguous 0 / + (5)
Demographics Old and/or young-age - -(2, 3, 4) 0 (5, 6)
population dependency
Urbanization Ambiguous - (3)
Income and wealth Income concentration + 0 (3)
distribution Wealth concentration +
Capital income share +
Note: the qualitative results listed in the last column of this table summarize significant signs of saving regressors in the
corresponding tables and columns of the following five studies: 1. Corbo and Schmidt-Hebbel (1991) (Table 4); 2.
Masson, Bayoumi, and Samiei (1995) (Table 2, "restricted model" column); 3. Edwards (1996) (Table 2, column 5); 4.
Dayal-Ghulati and Thimann (1997) (Table 4, column 2); 5. Bailliu and Reisen (1998) (Table 1, columns 3 and 4); and
6. Haque, Pesaran, and Sharma (1999) (Table 6, columns 4 and 5). Significant coefficient signs are identified by a plus
or a minus. Results identified by a zero mean either an insignificant coefficient in the corresponding column of the
original study or, when the variable is omitted from the particular specification reported in the column, a significant or
insignificant variable in a different column of the same table.
26
Table 2
Saving measures: availability and basic properties
(a) Sample composition
All LDC OECD
1970-79 267 132 135
1980-89 436 251 185
1990-95 169 92 77
Total 872 475 397
(b) Correlation matrix of alternative saving rate definitions
(IFull sample: upper triangle. Cross section: lower triangle)
GNS / GNDI GPSI GPDI GPS/ GPDI GPS/ GPDI GPSI GPDI
(PA) (PU) (CA) (CU)
GNS/GNDI 1.00 0.82 0.82 0.85 0.85
GPS/GPDI (PA) 0.89 1.00 0.95 0.94 0.91
GPS/GPDI (PU) 0.92 0.96 1.00 0.92 0.96
GPSIGPDI (CA) 0.94 0.94 0.95 1.00 0.97
GPS/GPDI (CU) 0.94 0.91 0.97 0.98 1.00
(c) Saving Ratios: Descriptive statistics
(Full sample)
Mean Std Dev Min Max
GNS/GNDI 0.206 0.075 -0.147 0.486
GPS/GPOI (PA) 0.193 0.083 -0.253 0.461
GPS/GPDI (PU) 0.215 0.081 -0.077 0.462
GPS/GPDI (CA) 0.210 0.085 -0.166 0.457
GPSIGPDI (CU) 0.226 0.084 -0.166 0.466
Note: Approximate standard errors are 0.031 for the full-sample correlations and 0.118 for the
cross-section correlations.
GNS = Gross National Saving, GNDI = Gross National Disposable Income.
GPS = Gross Private Saving, GPDI = Gross Private Disposable Income (4 alternative
definitions, as in the text).
27
Table 3
Correlation matrix of core private saving determinants
(Full sample: upper triangle. Cross section: lower triangle)
GPS/ Real Real Real int. M21GNP Terms of Urbani- Old Young Gvt. Pr.Cr. Inflation
GPDI GPDI GPDI rate Trade zation depen- depen- Saving Flow/GP rate
Growth Ratio dency dency IGPDI Dl
GPS/GPDI 1.00 0.52 0.38 0.22 0.42 0.03 0.36 0.33 -0.51 -0.13 0.21 -0.36
Real GPDI 0.66 1.00 0.12 0.14 0.52 -0.11 0.84 0.83 -0.88 -0.11 0.16 -0.25
Real GPDI growth 0.58 0.41 1.00 0.25 0.14 0.14 0.10 0.06 -0.15 -0.09 0.22 -0.31
Real int. rate 0.41 0.26 0.42 1.00 0.20 0.03 0.12 0.14 -0.23 -0.25 0.23 -0.63
M2/GNP 0.58 0.60 0.52 0.31 1.00 -0.09 0.41 0.48 -0.62 -0.02 0.18 -0.36
Terms of Trade -0.26 -0.15 -0.01 0.00 -0.05 1.00 -0.03 -0.13 0.10 0.17 0.04 -0.04
Urbanization ratio 0.48 0.87 0.35 0.15 0.48 -0.09 1.00 0.65 -0.75 -0.01 0.14 -0.16
Old dependency 0.48 0.79 0.29 0.18 0.64 -0.11 0.62 1.00 -0.85 -0.18 0.06 -0.24
Young dependency -0.63 -0.86 -0.46 -0.22 -0.70 0.12 -0.75 -0.87 1.00 0.07 -0.18 0.28
Gvt. Saving / GPDI 0.02 0.13 0.14 0.01 0.09 0.04 0.27 0.00 -0.07 1.00 0.16 0.26
Pr. Creditflowl 0.59 0.43 0.62 0.29 0.48 -0.05 0.43 0.25 -0.44 0.31 1.00 -0.33
GPDI
Inflation rate -0.36 -0.20 -0.31 -0.56 -0.48 -0.02 0.01 -0.20 0.18 0.03 -0.23 1.00
DESCRIPTIVE STATISTICS
(Full sample)
Mean Std Dev Min Max
GPSIGPDI 0.201 0.081 -0.253 0.461
Real GPDI 7.898 1.314 4.655 9.729
Real GPDI growth 0.019 0.055 -0.317 0.374
Real int. rate 0.000 0.074 -0.404 0.262
M2/GNP 0.491 0.236 0.128 1.466
Terms of Trade 0.017 0.152 -0.765 0.705
Urbanization ratio 0.595 0.229 0.055 1.000
Old dependency 0.129 0.068 0.047 0.276
Young dependency 0.535 0.221 0.227 0.992
Gvt. Saving/GPDI 0.070 0.069 -0.112 0.475
Pr. Credit flow / GPDI 0.032 0.058 -0.210 0.496
Inflation rate 0.089 0.076 -0.379 0.401
Note: Approximate standard errors are 0.034 for the full sample correlations and 0.118
for the cross-section correlations.
28
Table 4
Private saving: Alternative estimators, full sample
(Dependent variable: Gross private saving/GPDI)
1 2 3 4 5 6
Estimator OLS-CS OLS-Static OLS-Pool Within GMM-Diff GMM-Syst
Regression Levels Levels Levels Devia. Differences Levs - Diffs
Instruments - - - from mean Levels Diffs - Levs
Lagged private saving rate - - 0.832 0.570 0.302 0.587
(28.12) (14.699) (3.855) (9.254)
Real per-capita GPDla 0.046 0.048 0.010 0.068 0.069 0.049
(3.925) (4.108) (2.868) (4.914) (2.877) (2.458)
Real growth rate of per-capita GP[)lb 0.480 0.300 0.406 0.340 0.271 0.450
(0.971) (5.008) (8.62) (8.062) (3.741) (5.828)
Real interest ratea C 0.154 -0.122 0.032 0.049 -0.401 -0.253
(0.982) (-1.964) (1.347) (1.242) (-5.588) (-5.011)
M2/GNP 0.041 0.044 0.012 -0.035 -0.171 -0.020
(1.168) (1.845) (1.301) (-2.227) (-4.139) (-0.562)
Terms of tradea -0.089 0.009 0.006 0.036 0.109 0.078
(-3.142) (0.468) (0.848) (3.661) (5.676) (5.096)
Urbanization ratio -0.127 -0.115 -0.023 0.004 -0.070 -0.382
(-2.5) (-3.229) (-1.939) (0.045) (-0.508) (-3.538)
Old dependency ratio -0.437 -0.623 -0.086 -0.249 -0.168 -0.655
(-2.353) (-3.477) (-2.16) (-2.252) (-0.638) (-3.069)
Young dependency ratio -0.107 -0.143 -0.012 0.104 -0.155 -0.299
(-1.685) (-2.102) (-0.815) (2.437) (-1.846) (-4.017)
Government saving/GPDI -0.201 -0.065 -0.057 -0.154 -0.203 -0.285
(-0.976) (-0.89) (-2.367) (-4.605) (-2.618) (-5.097)
Private credit flow/GPDI 0.904 -0.003 -0.129 -0.114 -0.192 -0.318
(2.029) (-0.058) (-4.312) (-3.772) (-2.188) (-3.989)
Inflation ratea,C -0.031 -0.187 0.052 0.123 -0.134 0.143
(-0.212) (-2.918) (1.61) (2.503) (-1.514) (2.034)
Wald test of joint significance (p-value) 0.000 0.000 0.000 0.000 0.000 0.000
Sargan test (p-value) - - - - 0.291 0.400
Test for 1st-order serial correlation (p-value) - 0.000 0.095 0.000 0.033 0.001
Test for 2nd-order serial correlation (p- - 0.000 0.578 0.922 0.081 0.121
value)
Test for 3d-order serial correlation (p-value) - 0.000 0.081 0.146 0.873 0.221
Number of observations (Number of 72 (72) 1148 (69) 1079 (69) 1010 (69) 872 (69) 872 (69)
countries)
Notes: T-statistics (in brackets) computed with heteroskedasticity-consistent standard errors.
a Expressed in logs (log of [1 +x} for the real interest rate and the inflation rate).
b Measured by the first difference of the log.
c Both the real interest rate and the inflation rate are bounded between -50 percent and 50 percent.
29
Table 5
Private saving: Alternative samples, system estimator
(Dependent variable: Gross private saving/GPDI)
1 2 3 4
Sample Full Bounded* LDC OECD
Lagged private saving rate 0.587 0.494 0.476 0.674
(9.254) (10.330) (17.820) (12.704)
Real per-capita GPDla 0.049 0.035 0.071 0.013
(2.458) (2.408) (7.473) (0.382)
Real growth rate of per-capita GPDlb 0,450 0.379 0.425 0.285
(5.828) (6.103) (13.282) (2.036)
Real interest ratea C -0.253 -0.162 0.002 0.020
(-5.011) (-3.408) (.084) (0.313)
M2/GNP -0.020 -0.007 0.024 0.028
(-0.562) (-0.262) (1.001) (1.989)
Terms of tradea 0.078 0.060 0.044 0.068
(5.096) (5.921) (4.875) (3.641)
Urbanization ratio -0.382 -0.241 -0.240 -0.080
(-3.538) (-3.452) (-5.101) (-1.751)
Old dependency ratio -0.655 -0.555 -1.370 -0.218
(-3.069) (-4.531) (-4.321) (-1.42)
Young dependency ratio -0.299 -0.275 -0.279 -0.068
(-4.017) (-5.607) (-5.816) (-0.639)
Government savinglGPDI -0.285 -0.172 -0.238 -0.112
(-5.097) (-3.782) (-8.333) (-2.782)
Private credit flow/GPDi -0.318 -0.316 -0.508 -0.085
(-3.989) (-5.791) (-9.955) (-2.427)
Inflation ratea' C 0.143 0.127 0.177 0.157
(2.034) (3.325) (4.181) (2.963)
Wald test of joint significance (p-value) 0.000 0.000 0.000 0.000
Sargan test (p-value) 0.400 0.174 0.292 0.942
Test for 1st-order serial correlation (p-value) 0.001 0.001 0.000 0.013
Test for 2nd-order serial correlation (p-value) 0.121 0.362 0.690 0.157
Test for 3d-order serial correlation (p-value) 0.221 0.404 0.353 0.889
Number of observations (Number of countries) 872 (69) 845 (73) 475 (49) 397 (20)
Notes: T-statistics (in brackets) computed with heteroskedasticity-consistent standard errors.
* Observations more than 4 Standard Deviations away from mean of variables are dropped.
a Expressed in logs (log of [1 +x] for the real interest rate and the inflation rate).
b Measured by the first difference of the log.
c Both the real interest rate and the inflation rate are bounded between -50 percent and percent.
30
Table 6
Private saving: Alternative definitions of the private sector, full sample, system estimator
(Dependent variable: Gross private saving/GPDI)
1 2 3 4
Private sector definition CU CA PU PA
Lagged private saving rate 0.593 0.582 0.483 0.587
(11.921) (13.697) (6.734) (9.254)
Real per-capita GPDIa 0.046 0.029 0.043 0.049
(3.345) (1.912) (2.412) (2.458)
Real growth rate of per-capita GPDIb 0.481 0.493 0.472 0.450
(8.943) (9.969) (6.274) (5.828)
Real interest ratea -0.135 -0.108 -0.249 -0.253
(-2.165) (-1.59) (-4.949) (-5.011)
M2/GNP 0.085 0.062 -0.026 -0.020
(3.374) (2.783) (-0.787) (-0.562)
Terms of tradea 0.078 0.080 0.062 0.078
(5.324) (6.529) (4.500) (5.096)
Urbanization ratio -0.197 -0.104 -0.337 -0.382
(-3.207) (-1.563) (-3.481) (-3.538)
Old dependency ratio -0.873 -0.752 -0.578 -0.655
(-4.934) (-4.084) (-3.273) (-3.069)
Young dependency ratio -0.148 -0.160 -0.321 -0.299
(-2.411) (-2.732) (-4.375) (-4.017)
Government saving/GPDI -0.296 -0.388 -0.238 -0.285
(-7.101) (-10.982) (-4.437) (-5.097)
Private credit flowlGPDI -0.297 -0.251 -0.245 -0.318
- (-4.624) (-4.897) (-3.392) (-3.989)
Inflation ratea C 0.219 0.247 0.164 0.143
(3.636) (4.17) (2.548) (2.034)
Wald test of joint significance (p-value) 0.000 0.000 0.000 0.000
Sargan test (p-value) 0.356 0.400 0.442 0.400
Test for 1st-order serial correlation (p-value) 0.000 0.000 0.002 0.001
Test for 2nd-order serial correlation (p-value) 0.168 0.190 0.159 0.121
Test for 3d-order serial correlation (p-value) 0.087 0.099 0.257 0.221
Number of observations (Number of countries) 774 (69) 746 (69) 880 (69) 872 (69)
Notes: T-statistics (in brackets) computed with heteroskedasticity-consistent standard errors.
a Expressed in logs (log of (1 +x] for the real interest rate and the inflation rate).
b Measured by the first difference of the log.
c Both the real interest rate and the inflation rate are bounded between -50 percent and 50 percent.
31
Table 7
Private saving: Additional explanatory variables, full sample, system estimator
(Dependent variable: Gross pfivate savingiGPD!)
1 2 3 4 5 6 7
Additional variables Curr. Acct. Govt. Income Oii Crisis Income TOT Peer.- Ex-post
Deficit Investment Uncertainty Dummy Perm.- Temp. Temp. Real int.
Lagged private saving rate 0.435 0.587 0.529 0.614 0.615 0.702 0.577
(10.873) (14.233) (13.733) (12.069) (12.818) (17.109) (9.362)
Real per-capita GPDla 0.049 0.025 0.033 0.042 - 0.037 0.038
(3.535) (1.240) (1.847) (2.469) (2.647) (1.640)
Real growth rate of per-capita GPDlb 0.288 0.317 0.417 0.462 0.384 0.381 0.431
(6.117) (5.25) (10.652) (6.516) (5.494) (9.085) (4.679)
Real interest ratea c -0.143 -0.242 -0.203 -0.223 -0.194 -0.072 -0.386
(-3.774) (-8.412) (-6.178) (-5.328) (-7.235) (-2.379) (-4.213)
M2tGNP 0.028 -0.031 -0.045 -0.011 0.002 0.041 -0.052
(1.192) (-1.144) (-1.649) (-0.363) (0.084) (2.000) (-1.481)
Terms of tradea 0.041 0.093 0.068 0.069 0.084 - 0.047
(3.946) (7.374) (5,747) (5.960) (8.469) (3.605)
Urbanization ratio -0.205 -0.271 -0.363 -0.347 -0.283 -0.274 -0.308
(-2.848) (-3.077) (-4.269) (-3.989) (-3.846) (-3.774) (-3.553)
Old dependency ratio -0.95 -1.009 -0.552 -0.593 -0.225 -0.593 -0.653
(-5.841) (-4.151) (-4.486) (-3.637) (-1.401) (-3.878) (-2.510)
Young dependency ratio -0.231 -0.454 -0.397 -0.294 -0.350 -0.204 -0.289
(-5.021) (-7.084) (-7.426) (4.963) (-6.424) (-4.924) (-3.746)
Government saving/GPDI -0.306 -0.277 -0.251 -0.286 -0.156 -0.174 -0.297
(-7.073) (-5.034) (-5.244) (-5.423) (-3.265) (-4.307) (-4.528)
Private credit flow/GPDI -0.075 -0.290 -0.246 -0.266 -0.376 -0.378 -0.222
(-1.364) (-3.726) (-5.896) (-3.871) (-5.805) (-6.932) (-2.409)
Inflation ratea C 0.107 0.067 0.137 0.175 0.106 0.164 -0.104
(2.506) (1.525) (2.893) (2.742) (2.556) (4.420) (-0.924)
Current account deficit/GPD1 -0.329 - - - - - -
(-9.443)
Government investment/GPDI - -0.251 -
(-6.802)
Future income uncertainty proxyd - - 0.007 -
(0.049)
Oil crisis dumMye - - - -0.011 -
(-3.770)
Permanent (log) real per capita GPDi - - - - 0.005
(0.277)
Temporary (log) real per capita GPOI - - - - 0.160 -
(1.404)
Permanent (log) terms of trade - - - - - 0.058
(5.298)
Temporary (log) terms of trade - - - - - 0.177 -
(9.974)
Wald test of joint significance (p-value) 0.000 0.000 0.000 0.000 0.000 0.000 0.000
Sargan test (p-value) 0.268 0.475 0.547 0.450 0.918 0.372 0.505
Test for 1st-order serial correlation (p-value) 0.001 0.001 0.000 0.000 0.000 0.000 0.002
Test for 2nd-order serial correlation (p-value) 0.378 0.159 0.328 0.127 0.287 0.196 0.229
Test for 3d-order serial correlation (p-value) 0.147 0.129 0.256 0.176 0.125 0.188 0.120
Number of observations (Number of 872 (69) 673 (62) 777 (60) 872 (69) 779 (62) 858 (66) 872 (69)
countries)
Notes: T-statistics (in brackets) computed with heteroskedasticity-consistent standard errors.
a Expressed in logs (log of [1 +x] for the real interest rate and the inflation rate).
b Measured by the first difference of the log.
c Both the real interest rate and the inflation rate are bounded between -50 percent and 50 percent.
d Square of one-period ahead forecast error.
e In the regression of Column 4, we considered 4 time dummies corresponding to the oil crisis years 1973, 1974,1979 and 1980. Although all four
coefficients were found to be negative, only those for the years 1973 and 1974 were significant. The coefficient reported in the table corresponds to the
1974 Dummy variable.
32
Table 8
National saving rate: Alternative estimators, full sample
(Dependent variable: Gross national saving/GNDI)
1 2 3 4 5
Estimator OLS-CS OLS-Pool Within GMM-Diff GMM-Syst
Regression Levels Levels Devia. Differences Levs- Diffs
Instruments - from mean Levels Diffs - Levs
Lagged national saving rate - 0.802 0.572 0.378 0.381
(34.2) (19.054) (6.143) (6.650)
Real per-capita GNDIa 0.043 0.008 0.064 0.070 0.102
(5.012) (3.009) (5.255) (1.501) (2.685)
Real growth rate of per-capita GNDIb 0.878 0.285 0.271 0.249 0.447
(3.216) (9.459) (10.07) (2.573) (4.831)
Real interest ratea C 0.023 0.0121 0.016 -0.333 -0.136
(0.288) (0.669) (0.649) (-2.503) (-1.215)
M2/GNP 0.089 0.021 -0.031 -0.154 -0.019
(2.854) (3.109) (-2.236) (-2.504) (-0.410)
Terms of tradea -0.032 0.015 0.045 0.084 0.057
(-1.242) (2.031) (4.746) (5.753) (5.243)
Urbanization ratio -0.044 -0.020 -0.048 0.031 -0.500
(-1.416) (-2.062) (-1.107) (0.383) (-3.373)
Old dependency ratio -0.571 -0.133 -0.480 -0.343 -0.772
(-3.537) (-3.409) (-4.599) (-1.225) (-1.687)
Young dependency ratio -0.016 -0.020 0.051 -0.066 -0.156
(-0.365) (-1.985) (2.100) (-.823) (-2.236)
Domestic credit flow/GNDI 0.061 -0.118 -0.107 -0.365 -0.359
(0.209) (-4.508) (-4.473) (-3.764) (-4.136)
Inflation ratea. C -0.012 0.104 0.148 -0.016 0.180
(-0.131) (3.977) (4.232) (-0.174) (2.044)
Wald test of joint significance (p-value) 0.000 0.000 0.000 0.000 0.000
Sargan test (p-value) - - - 0.070 0.156
Test for 1st-order serial correlation (p-value) - 0.033 0.000 0.000 0.000
Test for 2nd-order serial correlation (p-value) - 0.340 0.357 0.248 0.174
Test for 3d-order serial correlation (p-value) - 0.189 0.610 0.149 0.260
Number of observations (Number of 102 (102) 1836 (98) 1738 (98) 1640 (98) 1640 (98)
countries)
Notes: T-statistics (in brackets) computed with heteroskedasticity-consistent standard errors.
a Expressed in logs (log of [1 +x] for the real interest rate and the inflation rate).
bMeasured by the first difference of the log.
c Both the real interest rate and the inflation rate are bounded between -50 percent and 50 percent.
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