Keeping up appearances: US domestic extremist organizations and the effects of membership on domestic terrorism perpetrators

Figures & data

Table 1. Descriptive statistics.

Variable	Obs	Mean	Std. Dev.	Min	Max
Violent	1064	.628	.484	0	1
Indiscriminate Violence	1064	.093	.291	0	1
Lethality	1064	.521	.859	0	3
Group Membership	1064	1.159	.864	0	3
Islamist	1064	.367	.482	0	1
Far Right	1064	.414	.493	0	1
Marital Status	706	1.569	.681	1	4
Marital Status Recoded	1064	.244	.43	0	1
Employment	549	1.148	1.507	0	5
Employment Recoded	1064	.354	.479	0	1
Military	748	.353	1.024	0	6
Military Recoded	1064	.108	.311	0	1
Social Media	402	.734	.678	0	2
Social Media Recoded	1064	.277	.548	0	2
Internet	532	.91	.697	0	2
Internet Recoded	1064	.455	.67	0	2
Violent Crime	1064	.121	.327	0	1
FTO	1064	.243	.429	0	1

Table

Dependent Variable(s)	Independent Variable	Controls
Violence (model 1)	Group Membership	Islamist
Indiscriminate Violence (model 2)		Foreign Terrorist List (FTO)
Projected Lethality (model 3)		Far-Right
		Internet
		Social Media
		Military Service
		Violent Crime
		Employment Status
		Marital Status

Table 2. Analysis results.

	(1)	(2)	(3)
	Violent	Indiscriminate	Lethality
Group Membership
1. Informal	−.444**	−.91***	−.165
	(.202)	(.296)	(.158)
2. Formal	−.604**	−1.368***	−.926***
	(.29)	(.317)	(.235)
3. Political Movement	−1.838***	−1.294**	−1.587***
	(.413)	(.619)	(.389)
Islamist	1.869***	−.078	.759*
	(.584)	(.312)	(.401)
Far Right	1.139***	−.012	.253
	(.404)	(.196)	(.222)
Marital Status	−.351*	−.534**	−.04
	(.211)	(.222)	(.173)
Military	.639**	1.037***	.878***
	(.262)	(.231)	(.202)
Employment	−.031	.212	.178
	(.151)	(.196)	(.147)
Social Media	.215	.039	.007
	(.177)	(.298)	(.225)
Internet	.001	−.048	.016
	(.227)	(.212)	(.152)
Violent Crime	.828***	.443	.482**
	(.241)	(.358)	(.218)
FTO	−.21	−1.421**	−.522
	(.434)	(.612)	(.425)
_cons	−.203	−1.521***
	(.407)	(.271)
/cut1			.773***
			(.201)
/cut2			2.182***
			(.173)
/cut3			2.961***
			(.237)
Observations	1064	1064	1064
Pseudo R^2	.126	.11	.05

Robust standard errors are in parentheses

***p < .01, **p < .05, *p < .1.

Table 3. Substantive effects for models 1 and 2.

	Margin	Std Error	95% Conf. Interval
Violence
No Group	0.7378	0.0210***	0.6965–0.7792
Informal Group	0.6435	0.0411***	0.5629–0.7240
Formal Group	0.6061	0.6061***	0.5042–0.7080
Political Movement	0.3092	0.0828***	0.1469–0.4717
Indiscriminate Violence
No Group	0.1417	0.0254***	0.0919–0.1914
Informal Group	0.0623	0.0145***	0.0339–0.0906
Formal Group	0.0403	0.0103***	0.0202–0.0604
Political Movement	0.0433	0.0257*	−0.0071–0.0937

*p < 0.1 **p < 0.05 ***p < 0.01.

Table 4. Substantive effects for Model 3.

	Margin	Std Error	95% Conf. Interval
No Group
0 Fatalities	0.575	0.021***	0.534–0.616
1–20 fatalities	0.272	0.030***	0.214–0.331
>20 fatalities	0.076	0.011***	0.055–0.098
>100 Fatalities	0.077	0.020***	0.037–0.116
Informal Group
0 Fatalities	0.615	0.032***	0.551–0.678
1–20 fatalities	0.253	0.029***	0.195–0.310
>20 fatalities	0.067	0.013***	0.041–0.094
>100 Fatalities	0.066	0.018***	0.030–0.101
Formal Group
0 Fatalities	0.773	0.044***	0.687–0.860
1–20 fatalities	0.160	0.031***	0.100–0.220
>20 fatalities	0.035	0.008***	0.020–0.050
>100 Fatalities	0.032	0.014**	0.005–0.058
Political Movement
0 Fatalities	0.869	0.044***	0.783–0.955
1–20 fatalities	0.096	0.031***	0.034–0.157
>20 fatalities	0.019	0.008**	0.004–0.034
>100 Fatalities	0.017	0.008**	0.001–0.033

*p < 0.1 **p < 0.05 ***p > 0.01.

Figure 1. Substantive Effects of Group Membership on Violence (95% CI).

Figure 2. Substantive effects of group membership on indiscriminate violence (95% CI).

Figure 3. Substantive effects of group membership on projected lethality (95% CI).