Table VII:

Population Diversity and the Frequency of Civil Conflict Onset across Countries – Mediating Channels

Mediating channel:	Cultural fragmentation			Interpersonal trust			Preference heterogeneity
	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
	OLS	OLS	OLS	OLS	OLS	OLS	OLS	OLS	OLS
	Log number of ethnic groups	Annual frequency of new civil conflict onsets, 1960–2017		Prevalence of interpersonal trust	Annual frequency of new civil conflict onsets, 1960–2017		Variation in political attitudes	Annual frequency of new civil conflict onsets, 1960–2017
Population diversity (ancestry adjusted)	5.187*** (1.887)	0.316*** (0.114)	0.294*** (0.109)	−1.817** (0.848)	0.488** (0.221)	0.447* (0.236)	14.344** (6.675)	0.451** (0.219)	0.375 (0.254)
Log number of ethnic groups			0.004 (0.005)
Prevalence of interpersonal trust						−0.023 (0.026)
Variation in political attitudes									0.005 (0.006)
Continent/region dummies	×	×	×	×	×	×	×	×	×
Controls for geography	×	×	×	×	×	×	×	×	×
Observations	147	147	147	84	84	84	81	81	81
Partial R2 of population diversity	0.049	0.047	0.039	0.075	0.062	0.049	0.082	0.050	0.033
Adjusted R2	0.342	0.203	0.201	0.441	0.232	0.226	0.397	0.247	0.249
Effect of 10th–90th %ile move in diversity	2.136*** (0.777)	0.021*** (0.008)	0.020*** (0.007)	−0.104** (0.049)	0.029** (0.013)	0.026* (0.014)	0.824** (0.383)	0.027** (0.013)	0.022 (0.015)

Notes: This table exploits cross-country variations to demonstrate that the significant positive reduced-form influence of contemporary population diversity on the annual frequency of new PRIO25 civil conflict onsets during the 1960–2017 time period, conditional on the baseline geographical correlates of conflict, is at least partly mediated by each of three potentially conflict-augmenting proximate channels that capture the contribution of population diversity to (i) the degree of cultural fragmentation, as reflected by the number of ethnic groups in the national population (Columns 1–3); (ii) the diminished prevalence of generalized interpersonal trust at the country level (Columns 4–6); and (iii) the extent of heterogeneity in preferences for redistribution and public-goods provision, as reflected by the intra-country dispersion in individual political attitudes on a politically “left”–“right” categorical scale (Columns 7–9). For each of the three mediating channels examined, the first regression documents the impact of population diversity on the proximate variable in the channel, the second presents the reduced-form influence of population diversity on conflict, and the third runs a “horse race” between population diversity and the proximate variable to establish reductions in the magnitude and explanatory power of the reduced-form influence of population diversity on conflict. All three regressions for each channel are conducted using a common cross-country sample, conditioned by the availability of data on the relevant variables employed by the analysis of the channel in question. 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 regressions for the “cultural fragmentation” channel control for the full set of continent dummies (i.e., five indicators for Africa, Asia, North America, South America, and Oceania), whereas for the “trust” and “preference heterogeneity” channels, given the smaller degrees of freedom afforded by the more limited sample of countries, the regressions control for a more modest set of region dummies, including an indicator for Sub-Saharan Africa and another for Latin America and the Caribbean. Given that the unit of measurement for the variable reflecting the degree of intra-country dispersion in political attitudes has no natural interpretation, its cross-country distribution is standardized prior to conducting the relevant regressions. The estimated effect associated with increasing diversity from the tenth to the ninetieth percentile of its cross-country distribution is expressed in terms of (i) the actual number of ethnic groups in the national population in Column 1; (ii) the fraction of individuals in a country who “think that most people can be trusted” in Column 4; (iii) the number of standard deviations of the cross-country distribution of the national-level dispersion in political attitudes in Column 7; and (iv) the number of new conflict onsets per year in all the remaining columns. Heteroskedasticity-robust standard errors are reported in parentheses.

^***denotes statistical significance at the 1 percent level,

^**at the 5 percent level, and

^*at the 10 percent level.