Table 2.

Results of the Instrumental-Variable Analysis of the Impact of App Usage on Perceived Threat (N = 811)

Predictor	Coefficient	SD	z	p
Constant	4.788	0.805	5.94	< .001
Age	0.013	0.011	1.16	.247
Gender (male = 1)	–0.732	0.245	–2.99	.003
Smartphone (yes = 1)	0.465	0.360	1.29	.197
County seat (yes = 1)	–0.574	0.257	–2.23	.026
Reported damage	0.321	0.054	5.97	< .001
Distance to epicenter	0.0000179	0.000016	1.12	.262
Activated social-network size	–0.005	0.005	–0.95	.341
Number of outgoing calls	0.090	0.155	0.58	.564
Number of outgoing texts	–0.263	0.109	–2.41	.016
Internet-browser usage	–0.298	0.175	–1.70	.089
Communications-app usage	0.454	0.180	2.53	.011
Hedonic-app usage	–0.396	0.142	–2.80	.005
Functional-app usage	0.041	0.146	0.28	.781

Note: In this analysis, perceived threat was the censored dependent variable (left censored at 0 = 77, uncensored = 474, right censored at 10 = 583). Frequencies of usage of communications, hedonic, and functional apps after the earthquake were identified as endogenous variables, and the corresponding frequencies of usage of these apps prior to the earthquake were used as instrumental values. Activated social-network size refers to the number of people with social ties to the victim that the victim called in the 28 days after the earthquake. Number of outgoing calls and number of outgoing texts refer to the quantity of communications initiated by the earthquake victim. All usage frequencies were log-transformed in the analysis. Age, gender, a smartphone dummy (whether the victim used a smartphone or not), physical distance to the epicenter, reported physical damage, and a dummy for county seat were included as exogenous variables. The basic test of the model’s validity yielded a Wald χ² of 86.6, p < .001.