The role of governmental weapons procurements in forecasting monthly fatalities in intrastate conflicts: A semiparametric hierarchical hurdle model

Figures & data

Table 1. Periodisation of data for expanding window evaluation at time point $t\in \{\text{Jan}.2017,\dots ,\text{Dec}.2019\}$ and $s\in \{2,\dots ,7\}$ and forecasting.

	Evaluation	Forecast
Pre-training	Jan. 1990 to $(t-s-1)$	Jan. 1990 to Jul. 2020
Calibration	t – s	Aug. 2020
Training	Jan. 1990 to t – s	Jan. 1990 to Aug. 2020
Test	t	Oct. 2020 to Mar. 2021

Figure 1. Observed and predicted changes in fatalities ${\Delta }_{\mathit{ijt}}^s$ with s = 2 in June 2018 in a sub-sample of countries. The predictions are separated along Stage 1 (first row), Stage 2 (second row), and final predicted change to April 2018 (third row).

Table 2. Out-of-sample MSE and TADDA scores from the hierarchical hurdle model with and without the MCW-related covariates as well as the benchmark model.

	MSE			TADDA
S	MCW	No MCW	Benchmark	MCW	No MCW	Benchmark
2	0.033	0.034	0.045	0.016	0.016	0.151
3	0.035	0.037	0.046	0.017	0.017	0.138
4	0.037	0.040	0.050	0.018	0.017	0.140
5	0.038	0.042	0.048	0.018	0.018	0.151
6	0.036	0.043	0.050	0.018	0.018	0.142
7	0.037	0.048	0.052	0.017	0.020	0.151

Figure 2. Forecasted log changes ${\Delta }_{\mathit{ijt}}^s$ in fatalities to October 2020 (s = 2) and March 2021 (s = 7), focused on the border region between Nigeria, Niger, Cameroon, and Chad.

Table 3. The subset of the parametric estimates regarding the governmental procurement of weapons with s = 2 and training data from January 1990 to August 2020.

	Covariate	Estimate	Std. error	t-Value	p-Value
Stage 1	Military expenditure	0.0624	0.0511	1.2212	0.222
	Long-term import of MCW	−0.091	0.0453	−2.0075	0.0447
	Short-term import of MCW	0.1105	0.0286	3.8669	0.0001
Stage 2	Military expenditure	0.0917	0.0173	5.3150	<0.0001
	Distance to capital (CD)	0.0001	0.0001	1.2355	0.2167
	Long-term import of MCW (LT)	−0.0288	0.0229	−1.2530	0.2102
	Short-term import of MCW (ST)	−0.0642	0.0179	−3.5951	0.0003
	LT × CD	−0.0002	0.0000	−9.5278	<0.0001
	ST × CD	0.0000	0.0000	1.4594	0.1445
Stage 3	Military expenditure	0.1870	0.0438	4.2726	<0.0001
	Distance to capital (CD)	0.0020	0.0002	11.2856	<0.0001
	Long-term import of MCW (LT)	0.6842	0.0519	13.1847	<0.0001
	Short-term import of MCW (ST)	−0.0142	0.0418	−0.3397	0.7341
	LT × CD	−0.0009	0.0001	−12.7753	<0.0001
	ST × CD	−0.0002	0.0001	−3.5264	0.0004