We have shown that most malarial countries are poor, and certain countries that managed to completely eliminate malaria in recent times have had more rapid economic growth than their neighbors. But can we find any general, statistically convincing evidence that initial malaria prevalence and reductions in malaria affect economic growth? Would a reduction in malaria significantly improve the economic prospects of poor countries?
The most direct way to assess the causal effect of malaria on country economic performance is to look at the relationship between economic growth, initial malaria levels, and change in malaria over the same period. Above, we saw that countries with severe malaria in 1965 have had much lower economic growth in the subsequent 25 years, but this did not take into account the initial poverty of countries, nor did it consider the role of human capital levels, government policies, or geographical variables. After the role of human capital, policy, and geography are taken into account, it is generally found that poorer countries grow faster than richer countries, so if malaria were really just a proxy for poverty, one would expect malarial countries also to grow faster.32 ( In fact, over the 1965–1990 period, poor countries on average grew slower than rich countries, but poor countries also had lower initial human capital, followed less successful economic policies, and were disadvantaged geographically.)
Table 7 presents a cross-country empirical growth estimation in the style of Barro.33 Growth in GDP per capita over the 1965–1990 period is related to initial income levels, initial human capital stock, policy variables, and geographical variables. Human capital stock is measured by secondary education and life expectancy at birth. Policy is measured by trade openness over the period and an index of the quality of public institutions. The geographical variables include an indicator for the geographical tropics and the fraction of the population within 100 km of the coast. ( Gallup and others12 give a more detailed description of these variables.) To these well-researched predictors of economic growth, we add the malaria index in 1965 in Regression 1.
The malaria index for 1965 (Figure 3) is constructed similarly to the malaria index described above. It is the product of the fraction of the population living in areas with high malaria risk in 1965 times the fraction of malaria cases in 1990 that are due to P. falciparum.3,5,6 This assumes that the relative share of P. falciparum cases did not change substantially from 1965 to 1990. The change in the malaria index over the 1965–1994 period was constructed with a similar malaria index for 1994 (Figure 4).4–6
Countries with severe malaria in 1965 had much lower economic growth, amounting to 1.3% lower growth per year, even after other factors such as initial income level, overall health, and tropical location are taken into account.
Reductions in malaria over the 1965–1990 period, in addition to malaria levels in 1965, are associated with much higher economic growth, as shown in Regression 2 in Table 7. This corresponds to a 0.3% rise in annual economic growth for a 10% reduction in the malaria index. Over the 25-year period, the average reduction in the malaria index was 7% among countries that had malaria in 1965. By extrapolation far outside the observed sample variation, a country with its whole territory affected by 100% P. falciparum malaria is predicted to permanently raise its annual growth by 2.6% if it completely eliminates malaria! Unfortunately, no country came near to accomplishing this. Of the 14 countries in the sample with a malaria index 0.9 in 1965, only one reduced it significantly: the malaria index in Zimbabwe fell by one third.
Economic growth itself might be a cause of the observed malaria reductions if greater resources were made available for malaria control, or if a high institutional capacity were
TABLE 7 Growth of gross domestic product ( GDP )
Regression model†
3 4
Variable 1
1965–1990 2
1965–1990 1965–1990 (IV) 1965–1990 (non-Africa) 5
1965–1990 6
1980–1995
Log initial GDP per capita
Log initial secondary schooling 2.6
(8.07)**
0.1
(1.04) 2.6
(7.90)**
0.1
(0.90) 2.4
(7.54)**
0.1
(0.60) 2.5
(6.36)**
0.1
(0.62) 2.3
(8.04)**
0.1
(0.77) 3.6
(7.95)** 0.2
(0.62)