Table 2.

Random effects multilevel models (MLM-RE)

	3. Threshold 1000		4. Threshold 1000 with covariates		5. Threshold 25		6. Threshold 25 with covariates
Fixed Part	Estimate	SE	Estimate	SE	Estimate	SE	Estimate	SE
(Intercept)	9.668	8.248	5.916	6.058	−9.598	10.159	4.144	6.187
Temp B	0.384	1.557	−0.068	1.171	1.129	2.691	0.342	0.233
Temp W	0.045*	0.023	0.026	0.022	0.051	0.041	0.030	0.032
Tempt−1, B	−0.392	1.561	0.061	1.173	−1.131	2.697	−0.342	0.233
Tempt−1 W	0.013	0.024	−0.008	0.023	−0.008	0.033	−0.011	0.033
Precip B	1.420	3.386	0.134	2.560	3.349	7.045	−0.166	0.448
Precip W	0.014	0.072	−0.026	0.060	0.118	0.092	0.050	0.065
Precipt−1 B	−1.456	3.394	−0.154	2.560	−3.395	7.060	0.167	0.451
Precipt−1 W	0.029	0.073	0.018	0.073	−0.017	0.095	−0.049	0.081
Year W	−0.005	0.004	−0.003	0.003	0.005	0.005	−0.002	0.003
Pol. exclusiont−1 B			0.128	0.087			0.020	0.014
Pol. exclusiont−1 W			0.195**	0.088			0.014	0.067
Ln GDP capitat−1 B			0.014	0.014			−0.005	0.005
Ln GDP capitat−1 W			−0.119	0.076			−0.111***	0.041
Post-cold war B			−0.120	0.228			0.090	0.068
Post-cold war W			−0.030	0.030			0.072*	0.039
Conflictt−1 B			0.531***	0.099			0.997***	0.011
Conflictt−1 W			0.271***	0.061			0.443***	0.077
Random Part
Level 2: σ2	0.042		0.010		0.091		0.000
Level 1: σ2	0.055		0.045		0.097		0.073
Country VPC	43.6%		18.4%		48.3%		0.0%
Conflicts	98		98		226		226
σresiduals	0.229		0.208		0.305		0.270
σ reduction	26.9%		33.6%		30.0%		38.0%

Models 3–4 extend Burke et al. (1) model 2, models 5–6 extend Buhaug (2) model 7. Significance codes: ***P < 0.01, **P < 0.05, *P < 0.1. B, between countries; W, within country; σ is SD. VPC is the variance partition coefficient = σ²_country/(σ²_country + σ²_year). σ reduction (%) is the percentage decrease in the dependent variable (DV) σ compared to the residuals σ: (σ_DV - σ_res)/σ_DV. Linear MLM-RE models fit using maximum likelihood, 889 country–year observations. SEs are robust country-clustered.