The Long-Term Effects of Africa's Slave Trades - Social Sciences ...

Table 8: Testing potential channels of causality.
Without colonizer fixed effects With colonizer fixed effects
OLS IV OLS IV
coef s.e. coef s.e. coef s.e. coef s.e.
Dependent variable
Pre-colonial state dev. −.026 ∗∗ (.013) −.069 ∗∗∗ (.025) −.026 ∗ (.015) −.064 ∗∗ (.025)
Rule of law −.073 ∗∗∗ (.020) −.118 ∗∗∗ (.039) −.078 ∗∗∗ (.018) −.095 ∗∗∗ (.032)
Ethnic fractionalization .040 ∗∗∗ (.009) .065 ∗∗∗ (.018) .041 ∗∗∗ (.010) .066 ∗∗∗ (.019)
Cultural diversity .029 ∗∗∗ (.007) .050 ∗∗∗ (.014) .031 ∗∗∗ (.008) .051 ∗∗∗ (.014)
ln per capita GDP in 1950 −.026 (.020) −.058 (.038) −.030 (.021) −.062 (.037)
Notes: The coefficients and standard errors reported are for ln(exports/area). In the IV regressions,
the instruments are the four distances to the markets of demand in each of the four slave trades.
The colonizer fixed effects are indicator variables for the identity of the colonizer at the time of
independence. Coefficients are reported with standard errors in brackets.
∗∗∗ , ∗∗ , and ∗ indicate
significance at the 1, 5, and 10 percent levels.
effects of the slave trades may be through state development, domestic institutions,
or ethnic fractionalization, which is an important determinant of
domestic policies such as the provision of public goods. In 1950, nearly all
countries were still under colonial rule, and therefore a country’s domestic
institutions and policies were externally imposed. 26 If the slave trades affect
income through the development of domestic institutions and policies, then
we would expect the relationship between the slave trades and income to be
much weaker, or even non-existent, when a country’s institutions and policies
are determined externally by a colonial power. The weak relationship
between slave exports and 1950 income is consistent with this. 27
7 Robustness and Sensitivity Analysis
The first set of tests that I perform check the robustness of my results to
the construction of the slave export data. As I noted in Section 3, the data
used to construct the slave export estimates for the Saharan, Indian Ocean
26 In 1950 only four African countries were independent. Ethiopia had never been colonized,
while Liberia, South Africa, and Egypt had gained independence.
27 An alternative way of expressing this is that income in 1950 may not be a good
indicator of a country’s economic development at that time. High income may simply
reflect high levels of extraction by the colonizer rather than a good economic environment.
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