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Poverty and Inequality 603
primarily interested in the growth–inequality relationship (with one
inequality measure being the income share of the poor group), but they also
asked whether the poorest 20 percent of the population shared the benefits
of growth proportionally.
16
These authors conclude that the income share
of the poor tends to decline in the early stages of development but increases
in the long run.
This approach has received renewed attention recently. Romer and
Gugerty, Gallup, and Dollar and Kraay state that the growth elasticity
of the incomes of individuals in the bottom quintile is essentially equal
to one.
17
Timmer obtains a more modest elasticity of around 0.9.
18
Even
though these studies use the same data and similar econometric techniques,
they disagree on the issue of whether growth leads to a proportional increase
in the income of the poor – in other words, if the gains for the poor are
smaller than those of other groups.
The second approach to poverty and inequality measurement tracks
income poverty levels using an absolute poverty line and a standard poverty
measure. Ravallion, Ravallion and Chen, and Bruno employ absolute
poverty lines of one and two dollars a day to identify the poor and then
aggregate, using the most common measures of poverty, the head count
ratio and the per capita poverty gap.
19
These studies find that the growth
elasticity of the head count ratio is normally below a minus-two level. In
other words, when average income increases by 1 percent, the proportion
of poor declines by more than 2 percent. Hence, the results not only show
that the relation between growth and poverty reduction does not function
on a merely one-to-one basis, but they further imply that growth is the
main vehicle for poverty reduction.
Other authors such as Morley, De Janvry and Sadoulet, and Smolensky
also use poverty lines that combine an absolute and a relative compo-
nent, but their elasticities are highly sensitive to the location of the poverty
16
Irma Adelman and Albert Morris, Economic Growth and Social Equity in Developing Countries (Stan-
ford, CA, 1973); Montek Ahluwalia, “Inequality, Poverty and Development,” Journal of Development
Economics 2 (1976): 307–42;Montek Ahluwalia, Nicholas Carter, and Hollis Chenery, “Growth and
PovertyinDeveloping Countries,” Journal of Development Economics 6 (1979): 299–341.
17
Michael Roemer and Mary Kay Gugerty, “Does Economic Growth Reduce Poverty?” (Discussion
Paper no. 4,Harvard Institute for International Development, Harvard University, 1997); John Luke
Gallup et al., “Economic Growth and the Income of the Poor” (Harvard Institute for International
Development, Discussion Paper no. 36,Harvard University, 1999); David Dollar and Aart Kraay
“Growth Is Good for the Poor” (Mimeograph, Washington, DC).
18
Peter Timmer, HowWell Do the Poor Connect to the Growth Process (Cambridge, MA, 1997).
19
Martin Ravallion, “Growth and Poverty: Making Sense of the Current Debate” (Mimeograph, World
Bank, Washington, DC, 2000).