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International Convergence in Well-Being Indicators
Vanesa Jorda • Jose Marıa Sarabia
Accepted: 19 February 2014� Springer Science+Business Media Dordrecht 2014
Abstract We re-examine the concept of beta-convergence in living standards across
countries during the period 1980–2012. In this study, well-being is assessed using the
Human Development Index (HDI) which considers income aspects as well as social
indicators, thus reflecting the multidimensional nature of this process. The existence of
sigma convergence is evidenced in this study and hence beta convergence, as a necessary
condition, is also pointed out. However, the linearity of this process has been questioned.
Therefore, we apply a semiparametric specification of this process to the HDI and each of
its intermediate indices. These models allows for nonlinearities in the estimation of the
convergence speed. Our results reveal that absolute convergence in human well-being is
satisfactorily represented by the conventional linear specification. However the income and
education indices show nonlinear patterns. We also include structural variables to capture
differences in the steady-state (conditional convergence). Under this model, convergence
speed of all indicators is higher and the convergence process seems to be linear only for the
health index.
Keywords Well-being � Beta-convergence � Sigma-convergence � Semiparametric
regression � Human Development Index
1 Introduction
The study of convergence has risen to prominence among academics since the presentation
of the classical works of Solow (1956, 1957) and Swan (1956). Several papers have tried to
V. Jorda � J. M. Sarabia (&)Department of Economics, University of Cantabria, Av. los Castros SN, 39003 Santander, Spaine-mail: [email protected]
V. Jordae-mail: [email protected]
123
Soc Indic ResDOI 10.1007/s11205-014-0588-8
determine if there is a long-run tendency towards equalisation, a question that lies in the
heart of the convergence debate.
According to the Solow–Swan neoclassical growth model, if countries only differ in
their level of capital, poor countries tend to grow faster than developed nations due to the
assumption of diminishing returns of capital. This theory is the so called absolute beta-
convergence, which assumes that all economies in the world converge to the same steady
state. Much of the existing literature on convergence hypothesis (see e.g. de la Fuente
1997; Islam 2003; Sala-i-Martin 1996) supports the existence of divergence among world
economies. Therefore, it is concluded that the currently rich nations are expected to be
even wealthier in the future, hence leaving developing countries behind. Note however that
economies usually differ in technology, population growth and human capital. Therefore,
differences in the structural parameters would result in different steady states. This concept
is called conditional beta-convergence in the classical literature, which has been evidenced
by numerous studies (see e.g. Barro and Sala-i-Martin 1990, 1992; Sala-i-Martin 1996),
thus pointing out that when taking the structural characteristics into account, poor countries
converge to their own steady state faster than the advanced economies.1
The concept of sigma-convergence has also been widely studied given its close rela-
tionship with the concept of beta-convergence. It is assumed that there is sigma convergence
if the dispersion of per capita income decreases over time, whereas beta-convergence is
evidenced when poor countries grow faster than wealthy nations. To achieve sigma-con-
vergence, the growth rate of developing countries needs to be higher than those observed for
rich countries. In this sense, it is said the beta-convergence is a necessary condition for
sigma-convergence. It could be also possible that the poor countries grow so fast that they
leave the initially rich nations behind until the point to increase the dispersion of the variable
under study. As a consequence, we would observe sigma-divergence along with beta-
convergence patterns, thus revealing that beta-convergence is not a sufficient condition for
sigma-convergence (Sala-i-Martin 1996). Previous studies conclude the existence of sigma
divergence across world economies for the second half of the last century (Decancq et al.
2009; Milanovic 2005; Pritchett 1997; World Bank 2006), revealing that inequality across
countries tends to increase over time.
Conventionally, the specification of absolute beta-convergence focuses on testing a
common linear trend between growth rate of per capita income and the initial level of
output. This regression is augmented with structural variables for testing conditional beta-
convergence. A negative sign of the coefficient on initial per capita income is interpreted as
a support for convergence across countries. However, many authors have questioned the
assumption of linearity (Durlauf et al. 2001; Fiaschi and Lavezzi 2007; Huang 2005),
concluding the existence of multiple growth regimes associated with different levels of
development.
Traditionally, income variables have played a main role in the measurement of quality of
life. However, there is a discontent with the hegemony of per capita GDP as an indicator of
well-being since there are other relevant dimensions which are imperfectly captured by
purely economic variables. There is by now nearly consensus that development is a mul-
tidimensional concept, which, in addition to income, also should consider social indicators.
This line of argumentation has gained prominence among academics over the last decades,
thus resulting in many attempts to synthesize different aspects of well-being, in a composite
1 This specification of convergence has been criticized for the so-called Galton’s fallacy problem and theinability to reflect the existence of multiple poles that might lead to multiple stable steady state equilibrium(See, e.g. Quah 1993, 1996).
V. Jorda, J. M. Sarabia
123
index which offers a more comprehensive perspective of such a process than per capita
income alone.
In 1979, David Morris from the Overseas Development Council designed the Physical
Quality Life Index (Morris 1979) constructed by a weighted average of infant mortality,
literacy rate and life expectancy at age one. Becker et al. (2005) developed an indicator
which combined income and longevity for measuring well-being inequality. More recently,
there have been many attempts to construct a composite index centred on the notion that
development entails more than just economic aspects (see e.g. Alkire and Foster 2010;
Bilbao-Ubillos 2013; Edgier and Tatlidil 2006; Fakuda-Parr et al. 2009; Grimm et al. 2008;
Morrison and Murtin 2012).
This line of thinking has induced academics to test the convergence hypothesis in other
dimensions such as health and education. A theoretical framework of convergence in life
expectancy is developed in Mayer-Foulkes (2003), concluding the existence of conver-
gence clubs, whereas global convergence is found to be weak. This result is confirmed in
Sab and Smith (2001), who also point out the existence of strong absolute and conditional
convergence in education. Mazumdar (2003) tests the existence of convergence in five
dimensions of well-being, including calorie intake, life expectancy, infant mortality, per
capita GDP and adult literacy rate, concluding divergence in all variables except for
income among the advanced economies.
A natural extension of these works is to test the hypothesis of convergence in an
aggregate index of quality of life, considering jointly social factors and economic indi-
cators. Note that this approach makes it possible to draw general conclusions regarding the
evolution of cross-country patterns of quality of life. There have been many attempts to test
whether a catching-up process in human well-being has taken place in the last decades (see
e.g. Konya and Guisan 2008; Mayer-Foulkes 2010; Noorbakhsh 2006), concluding that
living standards have converged slowly over the last 30 years. Nevertheless, some authors
questioned the linearity of this process. Mayer-Foulkes (2010), using series of superposed
transitions and quantile regression, concluded that complex relations of divergence and
convergence exist in the components of the HDI. In fact, nonlinear parametric models,
such as the quadratic specification, have been also proposed as a possible approximation of
this phenomenon (Mazumdar 2002, 2003). Note, however, that the parametric approach
requires making a priori assumptions about the evolution of the convergence speed, thus
the model might present misspecification bias. We opt for a semiparametric specification
which lets the data describe by themselves the convergence/divergence process, thus
offering a complete and continuous panorama of the distributional patterns of well-being.
Through the more flexible methodology of partially linear models (PLM), this work
aims to provide a reappraisal of the convergence process in terms of quality of life, using
the Human Development Index (HDI) as an indicator of this phenomenon, for the period
1980–2012. Note that this is the first study that uses the HDI with the changes introduced in
2010, which are argued to reveal a complete new situation in several aspects of human
development (Klugman et al. 2011). This fact will allow us to compare our estimates with
previous results, in order to investigate if the recent modifications applied to this indicator
have affected the conclusions regarding the process of convergence in well-being.
According to the results obtained by Martınez (2012), the new version of the HDI presents
higher levels of inequality than its predecessor and similar inequality trends are observed
for both definitions except for leftist indices such as the Kolm measure. The previous result
would be related to the concept of sigma-convergence, but nothing is said about the
consequences of the modification of the HDI on beta-convergence patterns.
International Convergence
123
Having reached this point, it should be emphasised that considering the hypothesis of
convergence in a composite indicator presents some shortcomings that should be taken into
account (Mazumdar 2003). In fact, these are the same criticisms that are attached to any
multidimensional indicator of well-being, namely the arbitrarily of the weights and the lack of
meaningfulness of the resulting indicator. Therefore, we also adopt a dimension-by-dimen-
sion approach to obtain more detailed conclusions regarding convergence in living standards.
The rest of the paper is organised as follows. Section 2 describes the characteristics of
the HDI as an indicator of well-being. Section 3 relates the convergence hypothesis to the
non-income variables. A detailed explanation of the data used and the methodology
applied is presented in Sect. 4. Section 5 explores the hypothesis of sigma-convergence
and presents the evolution of global well-being inequality over the last three decades. Beta-
convergence is tested in Sect. 6 using non-parametric techniques. Finally, Sect. 7 includes
some conclusions and discusses possible policy implications.
2 Measuring Development: Beyond Income
Since it was launched in 1990, the HDI attracts a large amount of attention from the media,
academics and policymakers. The HDI was designed following the Sen’s capability
approach (Sen 1988, 1989, 1999) which considers development as a process of enhancing
individuals’ choices. This new paradigm of development was presented in the first Human
Development Report which stated:
Human development is a process of enlarging people’s choices. In principle, these
choices can be infinite and change over time. But at all levels of development, the
three essential ones are for people to lead a long and healthy life, to acquire
knowledge and to have access to resources needed for a decent standard of living.
(UNDP 1990, p. 10).
To materialise this eminently subjective concept into a single number, three dimensions
were proposed, which were considered essential to measure the complex reality of human
development. Therefore, the HDI is made up of three intermediate indices, using country-
level data on income, health and education, which reflect achievements in each dimension
respect to the subsistence value and the historical maximum value observed.
Since 2010, the HDI of the country i in year t is constructed using a geometric mean of
the three intermediate indices as follows:
HDIit ¼ Ihealthit � IEducation
it � IIncomeit
� �1=3:
The health index (Ihealthit ) is measured by life expectancy at birth (LE), which is con-
sidered an indicator of longevity. This indicator is standardised according to the following
expression:
Ihealthit ¼ LEit � LEmin
LEmax � LEmin
;
where the minimum is the so-called level of subsistence fixed at 20 years, and the upper
bound is the maximum value observed between 1980 and 2011,2 that is 85 which
2 The upper bounds of all sub-indicators have been redefined in order to avoid the practice of cappingvariables at the top of the distribution. Consequently, the new bounds has lead an increase in the variabilityof the intermediate indices and hence in the HDI.
V. Jorda, J. M. Sarabia
123
corresponds to Japan in 2011. It should be noted that life expectancy only measures years
of life, but no insights about the quality of these years are made. Notwithstanding its
limitations, life expectancy is the sole variable that has not been changed since the HDI
was launched, due to the scarcity of data on health indicators for long temporal periods
(Klugman et al. 2011).
The education index (IEducationit ) comprises two variables, expected years of schooling
(EYS) and mean years of schooling (MYS). These indicators replaced gross enrolment
ratios and literacy rates in 2010, since they were considered to have higher discriminatory
power than their predecessors (Klugman et al. 2011). The education component is, then,
computed with the geometric mean, given by:
IEducationit ¼ MYSit �MYSmin
MYSmax �MYSmin
� �� EYSit � EYSmin
EYSmax � EYSmin
� �� �1=2
:
MYS and EYS have lower bounds of zero given that societies would survive without
education. The maximum corresponds to Czech Republic in 2005 with 13.1 expected years
of schooling, whereas MYS variable has a fixed maximum of 18 years, which is achieved
in several developed countries. These variables have been introduced in 2010 substituting
adult literacy rate and the combined gross enrolment ratio. These indicators were con-
sidered uninformative since no discrimination across countries is provided, especially in
the developed nations whose literacy rates are superior to 95 %. Then, the introduction of
these variables has increased the variability of the education index and hence the dispersion
of the HDI, being consistent with the results obtained by Martınez (2012).
Income is represented by Gross National Income (GNI) per capita measured in PPP
2005 US dollars, to make incomes comparable across countries and over time. It should be
noted that income is regarded as the mean to acquire goods and services, concept which is
different to how much is produced in a particular economy. Thus, per capita GDP has been
replaced by per capita GNI in 2010, given that such a variable represents the economic
reality of countries more accurately, in terms of the capability approach, due to the con-
sideration of international aid and foreign remittances. The intermediate index of income
(IIncomeit ) is computed as follows:
IIncomeit ¼ ln GNIitð Þ � ln GNIminð Þ
ln GNImaxð Þ � ln GNIminð Þ ;
where the maximum value is 107,721 (per capita GNI for Qatar in 2011), whereas the
minimum value is fixed at the level of subsistence which is 100 US$. Logarithmic
transformation was introduced in 2001 with the objective to reflect that income is con-
ceived as a mean to purchase goods and services, thus the concavity of the logarithmic
function characterises impact of diminishing returns of income on well-being.
In spite of its popularity, the HDI has been highly criticised [see Kovacevic (2010) for a
review] on the grounds of construction (Kelley 1991), selection of variables (Srinivasan
1994; Alkire 2002), arbitrary weighting scheme (McGillivray and White 1993; Noo-
rbakhsh 1998), and redundancy with its components (Cahill 2005; McGillivray 1991;
Ravallion 1997).
Some authors argue that the HDI omits important aspects of well-being that should be
incorporated in the index. Among them, we emphasise democracy (Domınguez et al.
2011), social cohesion (Bilbao-Ubillos 2011), personal safety (Bilbao-Ubillos 2013) and
environment (Briassoulis 2001; Neumayer 2001; Sagar and Najam 1998). Distributional
aspects have also been proposed for its consideration in the construction of the index
International Convergence
123
(Alkire and Foster 2010; Hicks 1997; Seth 2010) since inequality in the different aspects of
well-being has a deep impact on the progress of a particular country. Conversely, some
authors have suggested removing the income component from the HDI (Anand and Sen
2000).
Concerning the construction of the HDI, two main criticisms need to be addressed. An
equal weight scheme seems to be arbitrary hence not based on social choice nor normative
arguments. Notwithstanding this subjective format, statistical methods (principal compo-
nents analysis) have been applied to determine the weights supported by the data, con-
cluding that the simple average is empirically justified (Ogwang and Abdou 2003). On the
other hand, the traditional simple average is considered problematic since the components
of the index are regarded as perfect substitutes, thus implying that the marginal rate of
substitution is constant. This axiom can lead to incongruent results, in the sense that the
maximisation of the HDI in a society may lead to corner solutions, promoting one
dimension and disregarding others (Klugman et al. 2011). The formula introduced in 2010
marks a conceptual change concerning the relationship between the three dimensions given
that some degree of complementarity is also considered.
Several studies point out that there is a high rank correlation of the HDI and its under-
lying components, reflecting a problem of redundancy in the information provided by the
composite index. This result implies that ‘‘assessing inter-country development levels on
any one of these variables yields similar results to those that the index itself yields’’
(McGillivray 1991, pp. 1462). Therefore, the HDI would not provide us with comple-
mentary information than the traditional indicator of development, i.e. per capita GDP,
provides. Note that the previous statement would lead to the loss of the relevance of this
study. Since there is apparently no difference between income and human development, the
conclusions reached by previous studies on the convergence hypothesis would apply.
However, it has been concluded that the distributions of income, health, education and the
HDI are remarkably different (McGillivray and Markova 2010; McGillivray and Pillarisetti
2004; Pillarisetti 1997), also pointing out different evolutions over time. This result
emphasises the point that the consideration of a growth-centred approach or a more com-
prehensive definition of human development strongly affects our assessment of progress
hence our conclusions about convergence might be also altered.
The criticisms exposed before suggest that the HDI is not an ideal indicator of well-
being. However, the assessment of quality of life is complex, abstract and difficult to
synthesise. Independently of its limitations, the HDI seems to be the most adequate alter-
native to perform cross-country analyses of well-being since it has homogeneous available
data for a wider period of time and for more countries than other related indices.
3 Convergence in Well-Being
The concept of convergence in well-being is essentially studied using inequality measures
of the composite indicators (see e.g. Decancq et al. 2009; McGillivray and Markova 2010;
McGillivray and Pillarisetti 2004). There is a common result which indicates that well-
being levels are converging over the time but at slow rate:
For most of the past 40 years human capabilities have been gradually converging.
From a low base, developing countries as a group have been catching up with rich
countries in such areas as life expectancy, child mortality, and literacy. A worrying
aspect of human development today is that overall state of converging is slowing—
V. Jorda, J. M. Sarabia
123
and for a large group of countries divergence is becoming the order of the day.
(UNDP 2005, pp. 25).
Since the concept of beta convergence was derived from the Solow model, its theo-
retical framework is especially suitable for income. The principal mechanism behind the
convergence hypothesis is the assumption of diminishing returns of capital. Accordingly,
the vast majority of the papers that test convergence in living standards focuses on income
variables whereas social aspects of development are assumed to play little role. However,
there have been few attempts to test the convergence hypothesis in a more comprehensive
indicator per capita GDP (Mazumdar 2002; Noorbakhsh 2006; Konya and Guisan 2008;
Konya 2011; Mayer-Foulkes 2010), thus extrapolating the concept of diminishing results to
the non-income dimensions of the HDI.
According to Noorbakhsh (2006), the concept of diminishing returns can be ‘‘equally
applicable’’ to the educational variables and health indicators of the HDI but with some
peculiarities. Diminishing returns were derived from the mobility of the capital in the pure
economic model. In contrast, for non-income aspects, they are linked to the assumption
that investment returns in education and health diminish with the level of investment. In a
country with low levels of primary education, relatively less investment is necessary to
increase the mean years of schooling than in a developed nation, since tertiary education is
the most expensive type of education. Therefore, investment returns to increase the mean
years of schooling and the expected years of schooling will be higher in countries with low
levels of education. Moreover, given the nature of the educational indicators considered in
the HDI, which are basically quantitative variables that do not account for the quality of
education, they have upper limits that make plausible the existence of a convergence
process across countries.
Similarly, for the health dimension, it is supported that investment returns in health are
higher in countries with low life expectancy, since less amount of investment is needed to
improve health levels in countries with high rates of mortality. In fact, according to the last
report of millennium development goals (MDG), a large proportion of the deaths of
children under five could be saved through low-cost prevention and treatment measures
(United Nations 2012). Moreover this type of medical research is easily exported to other
countries, whereas advanced medical technology is more difficult to be implemented in
developing countries mainly due to lack of suitable personnel which also increases the
amount of investment (Mazumdar 2000).
4 Data and Methodology
We use the most recent available data from International Human Development Indicators
(UNDP 2012) on the HDI and its three components for 132 countries in the period
1980–2012 with different data frequency. For the period 1980–2005 we have 5-year
intervals and from 2005 to 2012 the data has annual frequency. Originally, our data
comprised only 105 countries, covering less than the 75 % of global population. We had
non-available data for 26 countries for one or more years before 1995. In order to offer
comparable results across periods and to not restricting the sample considerably, missing
values have been estimated. The estimation is based on two complementary methodologies
which jointly provide feasible and consistent results according to the sample: piecewise
cubic Hermite interpolating polynomial (PCHI) and the average rate of change, which is
International Convergence
123
used when PCHI offers unfeasible estimates or out of range results. After this procedure,
our dataset covers over 90 % of the world population during the whole period, including
132 countries whose indicators of income, health and education are available for thirteen
points of time.
To shed light on the well-being convergence process over the last three decades two
methodologies have been applied in this study. As a starting point, we calculate four
inequality measures which reveal the evolution of dispersion of national levels of well-
being over the study period. Therefore, in the first step we analyse the so called sigma-
convergence, not only using the classical indicator (i.e. the variance) but also considering
the Gini, Theil’s Entropy and the Atkinson indices. All measures indicate the amount of
dispersion of well-being distribution across countries, however different weighting
schemes are applied for each part of the distribution3 depending on the measure consid-
ered. The Theil index is a special case of the generalised entropy measures when the
sensitivity parameter is set to 1 (Cowell 2011). Such a parameter determines the weight
assigned to the upper tail, which in the case of the Theil index the same weight to all
countries, independently of its level of development. The Atkinson index is interpreted as
the proportion of total income that would be required to achieve an equal level of welfare.
This inequality measure also includes a parameter which is called inequality aversion
parameter, since it adjusts the index to be more sensitive to the lower tail as the parameter
increases (Atkinson 1970). The expressions of the Gini, the Theil and the Atkinson indices
are, respectively, the following:
GðtÞ ¼ 1
2n2lðY ðtÞÞXn
i¼1
Xn
j¼1
YðtÞi � Y
ðtÞj
������; ð1Þ
T ðtÞ ¼ 1
n
Xn
i¼1
YðtÞi
lðY ðtÞÞ logYðtÞi
lðYðtÞÞ
!
; ð2Þ
and
AðtÞe ¼ 1� 1
n
Xn
i¼1
YðtÞi
lðY ðtÞÞ
!1�e2
4
3
5
11�e
; ð3Þ
where xðtÞi denotes HDI or one of its intermediate indices for the country i at time t, l is the
arithmetic mean of the indicator under study, n is the number of countries, and finally, e is
the inequality aversion parameter of the Atkinson index.
Consequently, our analysis provides a broad picture of the evolution of inequality over
the last 30 years which allows us to determine whether distances between countries have
been reduced in terms of well-being. As stated before, a necessary condition for sigma
convergence is that beta-convergence also takes place, thus implying that developing
countries increase their levels of HDI relatively faster than the advanced nations.
The hypothesis of absolute beta-convergence is evidenced when there is a negative
relationship between the value of a variable at the beginning of the period and its growth
rate, which conventionally is tested using the following model:
3 The inclusion of other measures to determine the dispersion of the distribution, responds to the problemspresented by the variance, which is ‘‘unsatisfactory in that were we simply to double everyone’s incomes(and thereby double mean income and leave the shape of the distribution essentially unchanged)’’ (Cowell2011, 27).
V. Jorda, J. M. Sarabia
123
_yi ¼ aþ byi0 þ eit; ð4Þ
where yi0 is the logarithm of the HDI or any intermediate index which are denoted as Yit,
_yi ¼ ð1=TÞ ln ðYit=Yi0Þ is the growth rate of Yit and, finally, eit is the unexplained residual.
Positive values of the b parameter imply divergence, whereas negative values reveal
evidence of a catching-up process between developing and developed countries. Equation
(4) assumes that all countries of the sample converge to the same steady state. However,
nations have different structural features which lead to a multiple steady state equilibrium
(Sala-i-Martin 1996), which is related to the so-called conditional convergence hypothesis,
traditionally specified as an augmented regression of Eq. (4):
_yi ¼ aþ byi0 þ x0idþ eit; ð5Þ
where the matrix xi contains structural variables which are constant in the steady state. In
this study, a battery of conditioning variables is included along with regional dummy
variables for Latin America and the Caribbean and Sub-Saharan Africa.4 In particular, we
have included trade and foreign direct investment (FDI) both indicators as a percentage of
the GDP. According to Mayer-Foulkes (2010), these two variables are seen as indicators
of globalisation and technological change. As a measure of institutions, we have con-
sidered the Economic Freedom of the World (EFW) Index, which seems to represent
adequately the quality of national institutions with respect to economic performance
(Berggren 2003; De Haan et al. 2006).5 As domestic determinants of the expansion of
well-being, we have included public expenditures on health and on education as a per-
centage of the GDP. Domestic investment is expected to have a positive effect on
economic and human well-being which is measured with the variable gross capital for-
mation in relative terms to the GDP. Finally, following Noorbakhsh (2006), the number
of mobile lines (per 100 people) has been also considered to measure the level of
infrastructure. All variables have been drawn from World Development Indicators
Database (World Bank 2013) except the EFW index, which has been provided by
Gwartney et al. (2013).
It should be, however, noted that a number of studies have challenged the assumption of
linearity of income convergence. Using nonlinear specifications, it has been concluded that
the catching-up process is not adequately represented as a linear trend, thus classifying
countries into different groups which exhibit different convergence patterns (Azomahou et al.
2011; Durlauf 2001; Durlauf et al. 2001; Liu and Stengos 1999). Along this line, a gener-
alisation of the process of convergence in well-being is considered in Mazumdar (2002), who
includes quadratic and logarithmic terms to represent nonlinearities in the convergence
speed. Having reached this point, it is important to recall that parametric specifications
require making a priori assumptions about the functional form of the relationship under study.
On the other hand, Mayer-Foulkes (2010) performed quantile regressions to study non-
linearities in convergence in a number of indicators of quality of live. Note that this meth-
odology provides a restricted view of the process of convergence, given that it assumes
common distributional patterns within each quantile, not allowing for variability in the
4 We include only dummies for these two regions since they show remarkable different convergencepatterns than the rest of the world being characterized as the most unequal regions (see e.g. Chotikapanichet al. 2009).5 A number of studies demonstrated that there is a positive relationship between the EFW index and humanwell-being, see e.g. Goldsmith (1997), Gwartney and Lawson (2004), Gwartney et al (2010), Norton (1998).
International Convergence
123
direction and the intensity of this process.6 Therefore, we consider a more flexible model
which allows the data to describe by themselves the path of the convergence or divergence
process. Following the notation in Eqs. (4) and (5), we specify a semiparametric partially
linear regression (Wand 2005; Ruppert et al. 2003) for testing absolute and conditional beta-
convergence, given respectively by the following expressions:
_yi ¼ f ðyi0Þ þ git; ð6Þ
_yi ¼ f ðyi0Þ þ x0idþ git; ð7Þ
where yi0 denotes Yi0 expressed in natural logarithms, git is the error term identically and
independently distributed with mean 0 and variance r2g, and f(y0) is an unknown unidi-
mensional smooth function f ðY0Þ ¼ E _yjY0½ � which is represented by a linear combination
of polynomial functions, regression parameters and radial basis functions which need to be
chosen to be numerically stable. Therefore, the smooth function in Eq. (6) is expressed as a
radial basis function of degree three:
f ðY0Þ ¼ b0 þ b1yi0 þXK
k¼1
uk yi;0 � kk
�� ��3;
where bi for i = 0, 1 are the so-called fixed effects. The unknown vector of parameters
u ¼ u1; u2; . . .; uKð Þ0 follows a Normal distribution with mean 0 and variance r2uR0, being K
the number of bases, and kk are fixed knots calculated as qk ¼ k þ 1=K þ 2ð Þ;8 k ¼ 1; . . .;K. Note that if uk = 0 for all k, then the semiparametric model used in this
study turns out to be the linear specification of beta-convergence, since the last term
disappears.
The estimation is based on the so-called penalized spline smoothing, which minimizes
the following expression:
minb;u
y�Hhk k2þk3h0Dh; ð8Þ
where h = [b, u] is the parameter vector, H is a matrix that contains the polynomial basis
functions and the k radial basis functions, k3h0Dh is called roughness penalty since it
penalises fits that are too rough (Ruppert et al. 2003). The first parameter k[ 0, estimated
by restricted maximum likelihood, determines the amount of smoothing, thus controlling
the trade-off between roughness and goodness of fit. Finally, D is a block identity penalty
matrix whose first two elements are zero given that the fixed effects (intercept and linear
term) are not penalised.
The solution of the optimisation problem in Eq. (8) is the estimator matrix:
h ¼ ðH0Hþ k3DÞ�1Hy where y ¼ Sky;
being Sk ¼ H0ðH0Hþ k3DÞ�1H the so called hat matrix.
We also compute a test to analyse the adequacy of the semiparametric models with
respect to the linear specifications in Eq. (4) and (5) respectively (Crainiceanu and Ruppert
6 Note that Mayer-Foulkes (2010) focuses on the dimensions of the HDI rather than the composite indexand then no global conclusions can be achieved in terms of well-being since these different componentsshow different convergence patterns. In fact, as stated in this paper ‘‘Each human development componentfollows its own set of transitions’’, Mayer-Foulkes (2010, pp. 28).
V. Jorda, J. M. Sarabia
123
2004). Assuming that u is identically and independently distributed with mean 0 and
variance G ¼ r2uI, the null hypothesis u1 = u2 = … = uk is equivalent to r2
u ¼ 0:
H0 : r2u ¼ 0;
Ha : r2u [ 0:
Note that if the null hypothesis is no rejected, convergence in human development is
correctly represented by the conventional linear model. Otherwise, a more flexible semi-
parametric approximation is required.
We use the restricted log-likelihood ratio test (RLRT) expressed as follows:
RLRT ¼ supHa[H0
RELðh; r2e ; kÞ � sup
H0
RELðh; r2e ; kÞ;
where REL is the restricted maximum likelihood for the non-restricted model (PLM) and
the restricted specification (parametric model) respectively.
The computation of RLRT7 is relatively simple, however the derivation of its distri-
bution under the null has to be bootstrapped since the observations of the dependent
variable are not independent under the alternative. Therefore, the asymptotic probabilistic
theory does not hold.
5 Well-Being Inequality and Sigma Convergence
As a preliminary analysis, in this section we investigate sigma-convergence in the HDI and
each of its intermediate indices. This concept of convergence assumes that dispersion from
the cross-country mean tends to decrease over time (Barro 1991; Barro and Sala-i-Martin
1992). In the empirical literature, the variance of the logarithm of the variable under con-
sideration is the most commonly used measure of dispersion. We also have considered three
additional measures of inequality: the Gini [Eq. (1)], the Theil [Eq. (2)] and the Atkinson [Eq.
(3)] indices, whose evolution over the last three decades is presented in Fig. 1. To facilitate
the comparison of results, inequality has been normalised to be 100 in 1980.
Convergence trends are observed for each component although the intensity of this
process varies across dimensions. The dispersion of the educational indicator decreases
continuously during the entire period, thus experiencing the greatest fall of inequality,
ranged from 35 to 60 % depending on the inequality measure analysed. Such convergence
has its origin in the increase of the mean years of schooling, which has been doubled in the
last 40 years, thanks to the efforts in education performed in developing countries, espe-
cially in Asia (Morrison and Murtin 2012; World Bank 2006). Even when notable
achievements have been accomplished in developing countries in terms of education, it
should be noted that, this trend can be interpreted as an artificial convergence pattern due to
the upper limit that characterizes the educational variables included in the HDI (Neumayer
2003; McGillivray and Pillarisetti 2004).
In line with previous investigations, the fall of health inequality has been remarkably
lower, ranging from 15 to 30 % over the last three decades (McGillivray and Markova
2010). A process of divergence is observed in this dimension during the nineties decade as
7 For a detailed explanation of the procedure for testing the null hypothesis of non-significance of thevariance component in linear mixed models with one variance component see Crainiceanu and Ruppert(2004). In that paper the finite and asymptotic distribution of the RLRT is derived to provide consistentresults.
International Convergence
123
a consequence of the rapid extension of AIDS in Sub-Saharan Africa (Becker et al. 2005;
Neumayer 2003), effect partially offset by the decrease in infant mortality (Deaton 2004).
This trend is also driven by the health crisis in most Eastern European countries derived
from social upheaval, alcohol and tobacco consumption (McMichael et al. 2004; Moser
et al. 2005). Conversely, much more egalitarian distribution is observed for the second half
of the study period, mainly due to the enhancement of life expectancy in East and South
Asia and in the North of Africa (Goesling and Firebaugh 2004).
Income inequality has received by far more attention than the other dimensions. It is
well-known that cross-country inequality has increased over the second half of the last
century (see e.g. Milanovic 2005; Pritchett 1997; World Bank 2001). In spite of the success
of Asia which rapidly converged to the incomes of developed countries in the last 30 years,
the failure of Africa in the eradication of poverty has led to the increase of income
disparities. Notwithstanding this trend, income inequality across countries has been
reduced by about 10 % over the last 30 years, thanks to the strong convergence process
that took place in the last decade. According to Decancq (2011), the fall of unweighted
income inequality over the last decade would reveal that the financial crisis has affected to
wealthiest countries more than proportionally.
In line with previous studies, our results reveal the presence of a global convergence
process in living standards during the study period (Decancq et al. 2009; Martınez 2012;
McGillivray and Markova 2010).8 Taking the study period as a whole, it is observed that
40
50
60
70
80
90
100
110
120
1980 1985 1990 1995 2000 2005 201040
50
60
70
80
90
100
110
1980 1985 1990 1995 2000 2005 2010
60
70
80
90
100
110
120
130
1980 1985 1990 1995 2000 2005 2010
70
80
90
100
110
120
1980 1985 1990 1995 2000 2005 2010
Education indexHDI
Health index Income index
Variance Gini Theil Atkinson
Fig. 1 Inequality in the HDI and its components (1980 = 100)
8 Note that in Decancq et al. (2009) the sensibility of the results to different trade-offs between dimensionsis investigated in relation to the evolution of multidimensional inequality in well-being convergence.Actually, multidimensional inequality is beyond de scope of this paper. In any case, it should be stated that if
V. Jorda, J. M. Sarabia
123
inequality in human development decreased about 20 % according to the Gini index and
about 40 % for the Theil and the Atkinson indices over the last three decades. However,
two phases are clearly distinguishable. A stagnation term is observed from 1980 to 2000
which is derived from the slight increase of disparities in income and health during that
period, which was offset by the strong fall in disparities in education. Conversely, the last
decade of the study period is characterized by a sharp process of convergence in quality of
life, given that all components of the HDI reduced its inequality levels considerably.
Note however that the patterns described previously do not apply for the variance
because, as an absolute indicator, it does not take into consideration the mean of the
distribution. It should be stated that, for variables that show sharply positive or negative
trends over time, the coefficient of variation would provide more realistic reflection of the
convergence or divergence process (Kenny 2005). In fact, a number of papers consider
relative measures of well-being inequality to study sigma-convergence (Marchante et al.
2006; Ferrara and Nistico 2013; Konya and Guisan 2008; Noorbakhsh 2006), which is also
convenient in this case since the mean of the HDI has increased considerably over the last
decades, from 0.433 in 1980 to 0.621 in 2012 (UNDP 2013). We have calculated per-
centage change of coefficient of variation which is called the rate of sigma-convergence
(O’Leary 2001). Therefore, negative values indicate convergence in the sense of sigma,
whereas positive trends point out divergence patterns. Table 1 shows the growth rate of the
coefficient of variation for the countries included in the sample, calculated for each
dimension of the HDI and the index itself in the whole period and within each decade.
As for the other inequality measures, once the mean is taken into account, countries
converge in the sense of sigma, which implies that the dispersion tends to decrease over the
time. However, different patterns are presented across dimensions. Whereas a continuous
decrease is observed for the dispersion of the education indicator, inequality in income and
health is characterised by some fluctuations. Focusing on the evolution of inequality in the
composite index, it is concluded that, as in the case of education, a smooth linear process of
convergence has taken place over the last three decades. These dynamics point out that
uneven behaviours of different aspects of development are hidden when studying con-
vergence in well-being composite indices. Notwithstanding this fact, it is also important to
remark that convergence in the considered indicators of quality of life has taken place
mainly during the last decade in all cases.
At this point, it could be relevant to decompose the Theil index in two components:
inequality within-regions and inequality between-region in order to study the patterns of
sigma convergence more in detail (for the regions and the countries included see
‘‘Appendix’’). Among the inequality measures used in this study, the Theil index is the
only additively decomposable indicator.9 This measure can be expressed in terms of the
inequality within regions (which is a weighted average of the inequality within each
region) and inequality between regions (which represents the level of inequality that would
be if there were no differences within regions) using the following expressions (Cowell
2011):
Footnote 8 continuedwe apply unidimensional inequality measures to the HDI, we are assuming some degree of substitution andcomplementarity among dimensions since the composite indicator follows a Cobb–Douglas type function.9 The Atkinson index is decomposable but not additively, and then an interaction term is involved. The Giniindex can be additively decomposable if there is no overlapping between groups, but since we are con-sidering a regional classification, this is not the case.
International Convergence
123
TB ¼Xnr
i¼1
sr
lr
lT
� �log
lr
lT
� �;
TW ¼Xk
j¼1
sr
lr
lT
� �Tr;
where, sr is the proportion of countries included in the region (given that we are measuring
unweighted inequality), lr and lT are, respectively, the mean of the region and the global
mean of the variable under study. Finally, Tr is the Theil index of the region.
The evolutions of both components over the study period are presented in Fig. 2. In
terms of education we see that both types of inequality decreased steadily during the last
30 years, thus resulting in a decrease of educational disparities. Disparities in health
presented an ascending pattern from 1980 to 2000 which was mainly driven by differences
between regions which increased by 25 % in the first 20 years. In contrast, inequality
within-regions presented a decreasing trend except for the second half of the eighties.
Income inequality within-region reported an ascending pattern from 1980 to 2000, while
differences between regions remained rather constant. These dynamics resulted in the
increase of overall income disparities observed previously. Consequently, the last decade,
is characterised by the fall of both components. Similar trends are reported for disparities
in human development. Inequality within regions decreased continuously over the last
three decades, while an increase of the differences across regions is observed during the
nineties, followed by a decade of convergence. Since we observed a decreasing pattern of
global inequality in well-being over the whole period (see Fig. 1), it can be concluded that
the decrease in the within- region component offset the increase in disparities between
regions during the nineties.
It should be emphasized that even when different patterns are observed across
dimensions there are also common features that should be highlighted. First, differences
between regions dominate global inequality, representing more than the 75 % of overall
disparities in all cases. This result would indicate that the regions considered are homo-
geneous groups, and hence the bulk of inequality comes from disparities between these
territories. Secondly, the within-region component decreased substantially in for all indi-
cators considered, thus indicating that there was a process of convergence within the
borders of the regions, which became even more homogeneous groups at the end of the
study period. Third, a decrease in the differences between regions is observed except for
income whose inequality levels between these territories remained constant. The fall of this
component would imply that additionally to the convergence observed within regions, the
differences across them were also reduced. To sum up, a process of convergence in the
HDI is observed within regions and at the same time, differences across regions have been
also reduced, thus resulting in a global convergence process in quality of life.
Table 1 Rate of sigma-convergence
1980–1990 1990–2000 2000–2011 1980–2011
HDI -0.0723 -0.0270 -0.1197 -0.2054
Education Index -0.1379 -0.1030 -0.1483 -0.3414
Health Index -0.0451 0.0325 -0.1227 -0.1351
Income Index -0.0040 0.0201 -0.0853 -0.0706
V. Jorda, J. M. Sarabia
123
6 Beta-Convergence in Well-Being
Table 2 presents the estimation results of absolute convergence according to Eq. (6) using
as dependent variable the growth rate of the HDI and its intermediate indices. For com-
parative purposes, we also present the conventional linear estimation of beta-convergence
[Eq. (4)]. According the parametric estimates, all dimensions show statistically significant
negative coefficients of yi0, thus suggesting a negative relationship between the growth rate
of the considered indicators and their value in 1980. In line with previous studies, the
magnitude of the coefficient is relatively low, but significantly higher than the convergence
rates reported by previous studies with similar time spans (Noorbakhsh 2006; Konya and
Guisan 2008, Mayer-Foulkes 2010). Since this is the first study that uses the new version of
the HDI, the previous result would suggest that the changes applied to the HDI in 2010 not
only changed the method to assess well-being levels. These modifications also reported
different convergence patterns that are more intense under the new normative framework.
It should be also noted that the speed of convergence differs across dimensions. In line
with Mayer-Foulkes (2010) and Neumayer (2003), the educational dimension has seen the
most intense process of convergence, with rates close to 4 %. In contrast, income shows
the lowest reduction in the gap between developed and developing countries. Conse-
quently, even when little advance have been achieved in income levels, significant
improvements in non-income dimensions and human well-being have been accomplished.
This result points out the relevance of considering non-income dimensions in the study
of convergence hypothesis, since their distributional patterns differ substantially from
income.
0.0000
0.0050
0.0100
0.0150
0.0200
0.0250
0.0300
0.0350
0.0400
1980 1985 1990 1995 2000 2005 20100.0000
0.0100
0.0200
0.0300
0.0400
0.0500
0.0600
0.0700
0.0800
1980 1985 1990 1995 2000 2005 2010
0.0000
0.0050
0.0100
0.0150
0.0200
0.0250
1980 1985 1990 1995 2000 2005 20100.0000
0.0050
0.0100
0.0150
0.0200
0.0250
0.0300
0.0350
0.0400
1980 1985 1990 1995 2000 2005 2010
Education indexHDI
Health index Income index
Within Between
Fig. 2 Decomposition of the Theil index in within- and between-region inequality components
International Convergence
123
According to the results of the RLRT test, the null hypothesis of linearity is rejected for
the income and education indices (see the last row in Table 2), given that the bootstrapped
p values are practically equal to zero. As a result, we might conclude that the convergence
process has been nonlinear for both indicators. This conclusion would imply that, using
parametric models, the convergence speed is overestimated or underestimated for some
levels of income and education. These dynamics are observed from Fig. 3 which shows the
estimated function f(yi0) with the corresponding 95 confidence interval for absolute con-
vergence. The parametric counterpart (yi0) and its confidence bands are also plotted.
Education shows a decreasing and convex pattern which approaches to a linear trend for
medium and high educational standards. In contrast, the speed of convergence is under-
estimated for less educated countries given that the parametric estimates lies below the
confidence bands of the PLM model. The fact that the speed of convergence is higher in
countries with low educational standards could be related with the promotion of primary
education by Millennium Development Goals. One of the main concerns of this global
partnership is to achieve universal primary education. Then, the efforts undertaken by the
international community would have focused on this type of education, thus accelerating
convergence in this part of the educational distribution.
The income dimension presents a high convergence speed for low developed countries,
whereas a stagnation phase is observed for medium developed economies, which seems to
turn into convergence for the most advanced nations. This conclusion is also found in other
studies of global income convergence (see e.g. Dobson et al. 2003), also being consistent
with the well-known fact of the twin-peaked income distribution (Quah 1993, 1996).
Previous studies point out that the income distribution has evolved from a unimodal
distribution (in the decades of sixties and seventies) to a bimodal shape (in 2000). This
change reflects two different dynamics of medium developed countries. On the one hand a
number of medium developed nations converged to the poorest economies, while the rest
converged to the wealthiest countries (Sala-i-Martin 2000). These two opposite trends
Table 2 Parametric and Semiparametric estimations. Absolute convergence
Variable HDI Education index Health index Income index
Parametric specification
yi0a -0.0196***
(0.0017)-0.0402**(0.0037)
-0.0147***(0.0023)
-0.0126***(0.0038)
Constant 0.0191***(0.0011)
0.0334***(0.0020)
0.0154***(0.0018)
0.0119***(0.0025)
Adj. R2 0.5325 0.6860 0.2732 0.1313
Semiparametric specification
f(yi0) Fig. 2a Fig. 2c Fig. 2e Fig. 2g
Smoothing parameter 564 2.084 2.497 1.014
RLRT testb 0.0000(1.0000)
19.7747(0.0000)
0.2115(0.1926)
19.0775(0.0000)
Number of observations: 132 countries
The dependent variables are de average growth rate of the variables in columns
*** Significance at 1 % level; ** significance at 5 % level; * significance at 10 % level. Standard errors inparenthesisa Bootstrapped standard errors (based on 999 simulations)b Bootstrapped p value in parenthesis (based on 10,000 simulations)
V. Jorda, J. M. Sarabia
123
seem to balance in the aggregate, thus explaining the flat shape of the convergence speed
for medium income countries. Therefore, an important part of the linear estimated trend
lies outside the nonparametric confidence interval, thus indicating that the conventional
specification to test beta-convergence would mask nonlinearities which are actually cap-
tured by the semiparametric model. On the other hand, semiparametric estimates reveal
that the speed of convergence of the health index and the HDI follow linear trends which
are analogous to the conventional convergence models since the parametric estimations lie
inside the confidence bands in both cases.
We have augmented Eqs. (4) and (6) with a set of conditioning variables which capture
the existence of specific characteristics in each country thus allowing for the existence of
different steady states. Estimated results for conditional convergence [Eqs. (5) and (7)] are
presented in Table 3. From the parametric models, it is observed that the estimates of the
speed of convergence increase substantially when structural variables are included. This
raise is particularly evident in the case of health and education, whose speed of convergence
under the conditional framework is almost double the rate of absolute convergence.10 It
-1.5 -1.0 -0.5
-0.0
050.
000
0.00
50.
010
0.01
50.
020
0.02
50.
025
HDI
HDI in 1980 (in log)
aver
age
grow
th r
ate
-3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0
0.00
0.02
0.04
0.06
0.08
Education Index
Education index in 1980 (in log)
aver
age
grow
th r
ate
-1.2 -1.0 -0.8 -0.6 -0.4 -0.2
-0.0
050.
000
0.00
50.
010
0.01
50.
020
Health Index
Health index in 1980 (in log)
aver
age
grow
th r
ate
-2.0 -1.5 -1.0 -0.5 0.0
0.00
0.01
0.02
0.03
0.04
Income Index
Income index in 1980 (in log)
aver
age
grow
th r
ate
(d)
(b)
(c)
(a)
Fig. 3 Nonparametric estimation of f(yi0) according to Eq. (6). In each case yi0 represents the naturallogarithm of the HDI or its intermediate indices. The solid blue line corresponds to the estimate of f(yi0) andthe dashed curves delimit the 95 % confidence bands. The solid green line represents the classical linearestimation of beta-convergence. (Color figure online)
10 The acceleration of the convergence process under the conditional framework is a common result in theliterature (see Noorbakhsh (2006) and Konya and Guisan (2008) for examples related to convergence inhuman well-being). Note that the absolute model implies that all countries converge to the same steady state,
International Convergence
123
should be also noted that, as in the case of the unconditional model, we observe higher rates
of convergence than those of reported by previous studies (Noorbakhsh 2006; Mayer-
Foulkes 2010), thus reinforcing the hypothesis that the changes applied to the HDI in 2010
have modified the concept of development and the evaluation of levels of quality of life, and
consequently, its distribution has been also affected.
We have included all the conditioning variables only in the model for the HDI, which
tests the hypothesis of convergence in well-being. Instead, for each individual component,
we only include the auxiliary variables that have influence on the particular dimension. In
the case of the educational component we have considered as conditioning variables the
public expenditure on education and the dummies for Sub-Saharan Africa and Latin
America. Both dummies are significantly negative, thus indicating that educational levels
in the steady state are lower in the countries that belong to these regions. Public expen-
diture in education would also show a positive effect on convergence in education, a result
that emphasizes the role of the public policies in the expansion of educational levels.
For the health dimension, the dummy variables have been also included along with the
public expenditure in health as a percentage of the GDP. The signs of the dummies are the
same as in the case of education, also suggesting that the health levels in the steady state
are lower in Latin American and African countries. The role of the public services in health
is significant and the sign of the coefficient indicates that it has a positive influence in the
enhancement of life expectancy.
For the Income component, we have included several conditioning variables since this
dimension is related with trade, FDI, domestic investment, and the EFW index. According
to the value of the coefficient on the EFW index and consistently with previous investi-
gations (Gwartney and Lawson 2004; De Haan et al. 2006), the quality of institutions
seems to have a positive and highly significant effect on the increase of income. Similarly,
there is a positive relationship between gross capital formation and economic growth. In
the case of trade as a percentage of the GDP we have obtained a negative coefficient value
which is in line with the results presented by Slaughter (2001). Note that the effect of trade
openness on economic growth is far from consensual. Some authors argue that there is a
positive relationship (see e.g. Frankel and Romer 1999), while others found a negative link
in a number of country case studies (Greenaway et al. 1998; Wacziarg and Welch 2008).
Staying in the middle, some studies have pointed out a conditional relationship which
depends on structural and geographical variables of the countries involved in international
trade agreements (Lundberg and Squire 2003; Rodrik et al. 2004). On the other hand, FDI
seems to have no effect on income growth, a result that was also obtained in previous
studies (Mayer-Foulkes (2010)). The rationale behind the null effect of external invest-
ments seems to be the low stock of capital in some developing countries. According to
Borensztein et al. (1998), FDI potentiates economic growth only when the host economy
has enough absorptive capability of advanced technologies. As observed for the other
dimensions, dummy variables are found to be negative since income levels at the steady
state are lower in these to regions.
For the model of the HDI that would test the hypothesis of convergence in human
well-being, we observe a significant relationship between the composite index and all
indicators that were significant for individual dimensions. Then, FDI is the sole variable
Footnote 10 continuedwhile the consideration of structural variables allows for the existence of multiple steady state equilibrium.Then, only countries that share these characteristics are converging to the same steady state, and this processshould be faster than universal convergence.
V. Jorda, J. M. Sarabia
123
Ta
ble
3P
aram
etri
can
dS
emip
aram
etri
ces
tim
atio
ns.
Condit
ional
conver
gen
ce
Var
iab
leE
du
cati
on
index
Hea
lth
index
Inco
me
index
HD
I
OL
Sa
PL
MO
LS
aP
LM
OL
Sa
PL
MO
LS
aP
LM
f(y i
0)
-0
.049
05
**
*(0
.00
65
1)
Fig
.2d
-0
.032
65
**
*(0
.00
33
8)
Fig
.2f
-0
.021
27
**
*(0
.0
03
58
)F
ig.
2h
-0
.037
14
**
*(0
.00
25
5)
Fig
.2b
Inte
rcep
t0
.03
53
6**
*(0
.00
22
9)
-0
.00
02
7(0
.00
17
8)
0.0
27
74
**
*(0
.00
21
6)
-0
.00
17
8*
(0.0
009
7)
-0
.004
60
(0.0
067
6)
-0
.02
01
1**
*(0
.00
67
6)
-0
.017
40
**
*(0
.00
27
0)
-0
.011
59
**
(0.0
05
09
)
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de
-0
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03
*(0
.00
00
1)
-0
.00
00
3*
(0.0
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)-
0.0
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02
**
(0.0
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-0
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02
**
(0.0
00
01
)
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0(0
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3)
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00
30
(0.0
00
17
)-
0.0
00
05
(0.0
004
1)
-0
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02
(0.0
00
09
)
EF
W0
.00
26
6**
*(0
.00
08
0)
0.0
02
82
**
*(0
.00
05
4)
0.0
01
17
**
*(0
.00
04
5)
0.0
01
30
**
*(0
.00
03
2)
Gro
ssca
pit
alfo
rmat
ion
0.0
00
31
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0.0
00
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0.0
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12
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7)
0.0
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(0.0
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)
Mo
bil
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3)
0.0
00
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**
*(0
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2)
Pu
bli
cex
pen
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tio
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0*
(0.0
00
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)0
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**
(0.0
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0.0
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41
**
(0.0
001
7)
0.0
00
31
*(0
.00
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7)
Pu
bli
cex
pen
dit
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ealt
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.00
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5**
*(0
.00
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5)
0.0
00
27
*(0
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5)
0.0
00
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**
(0.0
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0)
0.0
00
14
*(0
.00
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7)
Lat
inA
mer
ica
-0
.003
37
**
*(0
.00
09
5)
-0
.00
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8**
*(0
.00
08
2)
-0
.000
13
(0.0
003
8)
-0
.00
02
0(0
.00
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4)
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.002
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**
(0.0
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2)
-0
.00
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5**
(0.0
01
14
)-
0.0
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41
**
*(0
.00
05
1)
-0
.001
68
**
*(0
.00
05
8)
Su
b-S
ahar
anA
fric
a-
0.0
05
24
**
(0.0
02
37
)-
0.0
03
98
**
*(0
.00
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International Convergence
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V. Jorda, J. M. Sarabia
123
that seems to be no related with the enhancement of quality of life. Similar to the
results presented by Noorbakhsh (2006), the coefficient associated with trade is nega-
tive. The inverse relationship between openness and well-being seems to be driven by
its negative correlation with the income component. Negative coefficients are also
found for the dummy variables. Since we found empirical evidence that Latin America
and Sub-Saharan Africa would present lower levels of income, health and education at
the steady state, the levels of human development would be also lower. Congruently
with the regression results of individual dimensions, the rest of variables are signifi-
cantly positive.
According to the results of the RLRT test, the health component is the sole dimension
that is adequately represented by the conventional linear specification (see the last row in
Table 3), given that the bootstrapped p value is almost cero. In contrast, the null hypothesis
of linearity is rejected in the cases of income, education and human well-being. Using
parametric models for testing the convergence hypothesis in these indicators will over-
estimate or underestimate the convergence rate for some parts of the distribution.
To analyse how conditional convergence speed evolves with the level of development,
nonparametric estimates for each dimension are presented in Fig. 4. Conditional conver-
gence patterns tend to be similar to the absolute ones (see Fig. 3) but with higher slopes. In
-1.5 -1.0 -0.5
-0.0
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000
0.00
50.
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5
HDI
HDI in 1980 (in log)
aver
age
grow
th r
ate
-3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0
0.00
0.02
0.04
0.06
0.08
Education Index
Education Index in 1980 (in log)
aver
age
grow
th r
ate
-1.2 -1.0 -0.8 -0.6 -0.4 -0.2
-0.0
050.
000
0.00
50.
010
0.01
50.
020
0.02
5
Health Index
Health Index in 1980 (in log)
aver
age
grow
th r
ate
-1.5 -1.0 -0.5 0.0
-0.0
2-0
.01
0.00
0.01
0.02
0.03
0.04
Income Index
Income Index in 1980 (in log)
aver
age
grow
th r
ate
(a)
(d)
(b)
(c)
Fig. 4 Nonparametric estimation of f(yi0) according to Eq. (7). In each case yi0 represents the naturallogarithm of the HDI or its intermediate indices. The solid blue line corresponds to the estimate of f(yi0) andthe dashed curves delimit the 95 % confidence bands. The solid green line represents the classical linearestimation of beta-convergence. (Color figure online)
International Convergence
123
the case of education, we observe higher convergence speed for primary education, but the
change in the slope is less pronounced under the conditional model. Income dimension
presents high rates of convergence for poor countries as well as for wealthy nations, while
medium developing countries show a flat shape that again indicates the absence of con-
vergence, thus reinforcing the hypothesis of a convergence clubs pattern. As concluded by
the RLRT test, the convergence process of the HDI seems to be nonlinear in this case.
Medium developed countries slowed down the convergence speed, which can be derived
from the stagnation phase that we observed for the income dimension. Note that the
parametric estimation of convergence in human well-being and income lies completely
below the semiparametric estimates, non-overlapping in any case. This result along with
the higher slope observed for the convergence process in the least educated countries
would highlight the fact that semiparametric models report different convergence patterns
than those obtained using the classical linear specification. If the nonlinearities are ignored,
our estimates of convergence speed would be underestimated for some parts of the dis-
tribution, also distorting the design of international strategies to achieve convergence. Note
that some authors argue that more efforts are needed from donor countries and interna-
tional aid agencies to accelerate the process of convergence in lees developed countries
(Noorbakhsh 2006). This conclusion is also supported by our results, but according to the
semiparametric estimates, medium developed countries should be also considered as
possible recipients of these funds or other expansive policies, given the deceleration of
convergence in well-being observed in these countries.
7 Conclusions
In this paper we re-examine the hypothesis of beta-convergence in well-being across
different economies during the period 1980–2012. The HDI is used as an indicator of such
process, which considers education and health as essential as income in the measurement
of well-being. Specifically, we analyse the concepts of sigma-convergence, which assumes
that dispersion of living standards tends to decrease over time; and beta-convergence,
which implies a negative relationship between the initial levels of a particular indicator and
its growth rate. Conversely to previous studies which estimate parametric models focused
on a linear trend, we opt for a flexible semiparametric approach. This specification does not
require making a priori assumptions about the model specification thus letting the data state
by themselves how the convergence rate evolves as the level of human well-being
increases. For comparative purposes, the parametric model is also estimated and structural
variables are included to capture differences in the steady-state, which is associated with
the concept of conditional beta-convergence.
Our results point out that the gap between developed and developing countries has been
substantially reduced in a wide range of indicators of quality of life. The educational
dimension shows the greatest reduction, around 60 %, followed by health whose inequality
levels have fallen about 30 %, and finally, the income dimension only reduced its
inequality in 10 % over the study period. These trends have resulted in a much more
egalitarian distribution of human well-being than 30 years ago. We decompose the Theil
index in two components, which represent inequality within and between regions. This
analysis reveals that disparities in well-being are dominated by differences across regions,
which represent more than the 75 % of overall disparities. A decrease in inequality within-
V. Jorda, J. M. Sarabia
123
region is observed along with the fall of differences across regions, thus resulting in a
global process of convergence in quality of life.
Regarding beta-convergence, the results obtained from the classical linear analysis at
least suggest weak absolute convergence in living standards over the last 30 years. It
should be worth noting that the convergence rates obtained in this study using the new
framework of the HDI, are unambiguously higher than those of reported by previous
studies. This finding is robust to the introduction of conditioning variables which leads to
higher rates of convergence speed. Consequently, the changes applied to the HDI in 2010
affected substantially the method to evaluate well-being, thus redefining the convergence
patterns of this indicator.
The results of the RLRT test point out that the process of convergence has been
nonlinear for some of the indicators considered. In particular, PLM models reveal that
whereas the absolute convergence process in human well-being is adequately represented
by a parametric trend, conditional convergence shows nonlinear patterns. In fact, semi-
parametric estimates show that convergence in well-being seems to be slowed down for
medium developed countries, whereas for the advanced economies, the convergence
process is again accelerated. Our results suggest that, even when little advances have been
achieved in income levels, significant improvements in non-income dimensions and human
well-being have been accomplished. This conclusion highlights the relevance of consid-
ering non-income dimensions in the study convergence hypothesis, since their distribu-
tional patterns differ substantially from income.
This study reveals that some degree of equalisation in well-being levels has taken place
in the last decades. However, the convergence process is being rather slow and hence the
action of international organisations is essential to achieve faster rates of convergence.
International cooperation in social policies plays also a crucial role in increasing well-
being levels in developing countries in the near future, thus moving on the direction MDG.
Given that less developed countries have a scarcity of technological and capital resources
(UNDP 2003; WHO 2003) more efforts are needed from donor countries and international
aid agencies (Noorbakhsh 2006). In fact, the fulfilment of a global partnership seems to be
the key in achieving the eight targets of MDG by 2015 (United Nations 2012). Note that
medium developed countries should also be considered as possible recipients of these
funds or other expansive policies, given the deceleration of convergence in well-being
observed for these nations. The role of the national governments is also important espe-
cially in expanding schooling rates. Their efforts to improve primary care are also deter-
minant to enhance the quality of life (Kenny 2005), thus encouraging a catching-up process
between developing countries and leader economies.
Acknowledgments The authors thank the Ministerio de Economıa y Competitividad (Project ECO2010-15455) and the Ministerio de Educacion (FPU AP-2010-4907) for partial support of this work. Authors aregrateful for the constructive suggestions provided by the reviewers, which improved the paper substantially.
Appendix: Regions and Countries Included
Western Europe, North America, and Oceania: Australia, Austria, Belgium, Canada, Denmark, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Korea (republic of), Luxembourg,Malta, Netherlands, New Zealand, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom,United States
Arab States: Algeria, Bahrain, Egypt, Israel, Jordan, Morocco, Qatar, Saudi Arabia, Sudan, Syrian ArabRepublic, Tunisia, Yemen, United Arab Emirates
International Convergence
123
Appendix continued
East Asia and the Pacific: Brunei Darussalam, China, Fiji, Hong Kong, Indonesia, Kiribati, Lao People’sDemocratic Republic, Malaysia, Mongolia, Myanmar, Papua New Guinea, Philippines, Thailand, Tonga,Viet Nam
Europe and Central Asia: Albania, Armenia, Bulgaria, Cyprus, Estonia, Latvia, Lithuania, Moldova(Republic of), Montenegro, Romania, Russian Federation, Slovenia, Slovakia, Tajikistan, Turkey, Ukraine
Latin America and the Caribbean: Argentina, Belize, Bolivia (Plurinational State of), Brazil, Chile,Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guatemala, Guyana, Haiti,Honduras, Jamaica, Mexico, Nicaragua, Panama, Paraguay, Peru, Trinidad and Tobago, Uruguay,Venezuela (Bolivarian Republic of)
South Asia: Afghanistan, Bangladesh, India, Iran (Islamic Republic of), Nepal, Pakistan, Sri Lanka
Sub-Saharan Africa: Benin, Botswana, Burundi, Cameroon, Central African Republic, Congo, DemocraticRepublic of the Congo, Cote d’Ivoire, Gabon, Gambia, Ghana, Kenya, Lesotho, Liberia, Malawi, Mali,Mauritania, Mauritius, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, SouthAfrica, Swaziland, Tanzania (United Republic of), Togo, Uganda, Zambia, Zimbabwe
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