Table II:

Population Diversity and the Incidence or Onset 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)
	Probit	Probit	IV Probit	IV Probit	Probit	Probit	IV Probit	IV Probit
	Quinquennial PRIO25 civil conflict incidence, 1960–2017				Annual PRIO25 civil conflict onset, 1960–2017
Population diversity (ancestry adjusted)	13.366*** (3.700)	12.203*** (3.787)	14.304*** (3.652)	13.578*** (4.210)	6.172** (2.576)	6.356** (2.645)	7.066*** (2.594)	8.804*** (3.170)
Ethnic fractionalization		−0.399 (0.353)		−0.519 (0.332)		−0.084 (0.252)		−0.322 (0.280)
Ethnolinguistic polarization		0.049 (0.344)		0.322 (0.340)		0.172 (0.248)		0.334 (0.254)
Continent dummies	×	×	×	×	×	×	×	×
Time dummies	×	×	×	×	×	×	×	×
Controls for temporal spillovers	×	×	×	×	×	×	×	×
Controls for geography	×	×	×	×	×	×	×	×
Controls for institutions		×		×		×		×
Controls for oil, population, and income		×		×		×		×
Observations	1,270	1,045	1,583	1,311	5,452	4,377	6,996	5,757
Countries	123	121	150	147	123	121	150	147
Pseudo R2	0.416	0.440			0.131	0.161
Marginal effect of diversity	2.553*** (0.683)	2.261*** (0.709)	2.817*** (0.741)	2.595*** (0.850)	0.324** (0.139)	0.332** (0.140)	0.336** (0.133)	0.421** (0.170)
FIRST STAGE			Population diversity (ancestry adjusted)				Population diversity (ancestry adjusted)
Migratory distance from East Africa (in 10,000 km)			−0.068*** (0.006)	−0.066*** (0.006)			−0.068*** (0.006)	−0.066*** (0.006)
First-stage F statistic			145.394	99.876			151.502	102.614

Notes: This table exploits variations in repeated cross-country data to establish a significant positive reduced-form impact of contemporary population diversity on the likelihood of observing (i) the incidence of a PRIO25 civil conflict in any given 5-year interval during the 1960–2017 time period (Columns 1–4); and (ii) the onset of a new PRIO25 civil conflict in any given year during the 1960–2017 time period (Columns 5–8), conditional on ethnic diversity measures as well as the proximate geographical, institutional, and development-related correlates of conflict. 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 institutions include a set of legal origin dummies, comprising two indicators for British and French legal origins, as well as six time-dependent covariates, comprising 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 values of total population and GDP per capita. In Columns 1–4, all time-dependent covariates assume their average annual values over the previous 5-year interval, whereas in Columns 5–8, they assume their annual values from the previous year. To account for duration dependence and temporal spillovers in conflict outcomes, all regressions control for the lagged incidence of conflict, and the regressions in Columns 5–8 additionally control for a set of cubic splines of the number of peace years. 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 IV probit 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 marginal effect of a 1 percentage point increase in population diversity is the average marginal effect across the entire cross-section of observed diversity values, and it reflects the increase in either the quinquennial likelihood of a conflict incidence (Columns 1–4) or the annual likelihood of a conflict onset (Columns 5–8), both expressed in percentage points. 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.