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. Author manuscript; available in PMC: 2022 Sep 6.
Published in final edited form as: Econometrica. 2020 Mar;88(2):727–797. doi: 10.3982/ECTA13734

Table A.I:

Population Diversity and the Severity of Civil Conflict in Repeated Cross-Country Data

Cross-country sample: Old World
Global
Old World
Global
(1) (2) (3) (4) (5) (6) (7) (8)
OLS OLS 2SLS 2SLS OLS OLS 2SLS 2SLS
Quinquennial MEPV civil conflict 1960–2017
Quinquennial CNTS social conflict severity, index, 1960–2014
Population diversity (ancestry adjusted) 4.241*** (1.452) 4.089** (1.803) 4.159*** (1.531) 3.981** (1.987) 5.306** (2.350) 5.619*** (1.982) 5.679** (2.599) 6.106*** (2.289)
Continent dummies × × × × × × × ×
Time dummies × × × × × × × ×
Controls for temporal spillovers × × × × × × × ×
Controls for geography × × × × × × × ×
Controls for ethnic diversity × × × ×
Controls for institutions × × × ×
Controls for oil, population, and income × × × ×

Observations 1,270 1,045 1,576 1,311 1,144 924 1,430 1,165
Countries 123 121 149 147 123 120 150 146
Partial R2 of population diversity 0.009 0.006 0.006 0.005
Adjusted R2 0.630 0.614 0.082 0.104
Effect of 10th–90th %ile move in diversity 0.199*** (0.068) 0.183** (0.081) 0.276*** (0.102) 0.264** (0.132) 0.249** (0.110) 0.264*** (0.093) 0.370** (0.169) 0.405*** (0.152)
First-stage F statistic 150.323 101.923 147.137 93.983

Notes: This table exploits variations in repeated cross-country data to establish a significant positive reduced-form impact of contemporary population diversity on the severity of conflict, as reflected by (i) the maximum value of an annual ordinal index of conflict intensity (from the MEPV data set) across all years in any given 5-year interval during the 1960–2017 time period; and (ii) the maximum value of an annual continuous index of the degree of social unrest (from the CNTS data set) across all years in any given 5-year interval during the 1960–2014 time period, conditional on other well-known diversity measures as well as the proximate geographical, institutional, and development-related correlates of conflict. Given that both measures of conflict severity are expressed in units that have no natural interpretation, their intertemporal cross-country distributions are standardized prior to conducting the regression analysis. The controls for geography include absolute latitude, ruggedness, distance to the nearest waterway, the mean and range of agricultural suitability, the mean and range of elevation, and an indicator for small island nations. The controls for ethnic diversity include ethnic fractionalization and polarization. The controls for institutions include a set of legal origin dummies, comprising two indicators for British and French legal origins, as well as six time-dependent covariates that capture the average annual values over the previous 5-year interval of the degree of executive constraints, two indicators for the type of political regime (democracy and autocracy), and three indicators for experience as a colony of the U.K., France, and any other major colonizing power. The control for oil presence is a time-invariant indicator for the discovery of a petroleum (oil or gas) reserve by the year 2003. The controls for population and income are the time-dependent log-transformed average annual values over the previous 5-year interval of total population and GDP per capita. To account for temporal dependence in conflict outcomes, all regressions control for the value of the outcome variable from the previous 5-year interval. For regressions based on the global sample, the set of continent dummies includes five indicators for Africa, Asia, North America, South America, and Oceania, whereas for regressions based on the Old-World sample, the set includes two indicators for Africa and Asia. The 2SLS regressions exploit prehistoric migratory distance from East Africa to the indigenous (precolonial) population of a country as an excluded instrument for the country’s contemporary population diversity. The estimated effect associated with increasing population diversity from the tenth to the ninetieth percentile of its cross-country distribution is expressed in terms of the number of standard deviations of the intertemporal cross-country distribution of the outcome variable. Heteroskedasticity-robust standard errors, clustered at the country level, are reported in parentheses.

***

denotes statistical significance at the 1 percent level,

**

at the 5 percent level, and

*

at the 10 percent level.