Table 4. Sensitivity Analysis of Results of the Two-Part Model of the Frequency of Nonemergent Emergency Department (ED) Visits, Including Individuals With Emergent ED Visits

	Binary Hurdle Model (Logit)		Zero-Truncated Negative Binomial Model
	Coefficient	t Value	Coefficient	t Value
Constant	−3.144^*	−3.80	−17.107^*	−7.83
Predisposing characteristics
Age, years
45–64	−0.620^*	−7.53	−0.513^*	−2.28
≥65	−0.686^*	−5.27	−0.749^*	−2.02
Female sex	0.307^*	4.26	0.209	1.09
Race
Black	0.362^*	3.82	−0.728^*	−3.52
Other	−0.110	−0.78	−0.900^*	−2.68
Hispanic ethnicity	−0.013	−0.13	0.530^*	2.03
Education
High school	0.155	1.53	0.519^*	2.29
Bachelor's degree or more	−0.059	−0.45	0.850^*	2.89
Employed	−0.021	−0.22	0.159	0.80
Marital status
Widowed	0.001	0.01	0.512	1.52
Divorced	0.035	0.30	−0.182	−0.62
Separated	0.304^*	2.00	0.248	0.55
Never married	0.109	1.11	0.203	0.93
Able to speak English	0.289	1.76	0.788	1.55
More likely to take risks	0.026	0.26	0.161	0.73
Can overcome illness without medical help	−0.119	−1.23	−0.293	−1.29
Enabling resources
Income (% of poverty level)
<100 (poor)	0.652^*	4.77	0.170	0.59
100–199 (low income)	0.468^*	3.78	0.078	0.33
200–399 (middle income)	0.272^*	2.24	0.295	1.14
Health insurance
Public	0.170	1.59	0.297	1.40
Uninsured	0.101	0.85	0.481	1.85
Region
Midwest	0.341^*	2.69	0.014	0.05
South	0.158	1.24	−0.174	−0.66
West	0.202	1.51	−0.027	−0.09
Urban MSA	−0.105	−1.03	0.280	1.32
Need factors
Health status
Very good	0.270^*	1.99	−0.406	−1.11
Good	0.738^*	5.35	0.061	0.19
Fair	0.978^*	5.97	0.593	1.56
Poor	1.502^*	7.45	0.725	1.68
Mental health
Very good	−0.201^*	−1.96	0.255	0.96
Good	−0.050	−0.43	0.243	1.12
Fair	0.030	0.22	−0.121	−0.42
Poor	−0.060	−0.30	0.447	1.08
Hypertension	−0.084	−0.88	−0.247	−0.95
Coronary heart disease	−0.096	−0.66	−0.081	−0.20
Angina	0.207	0.94	1.017^*	1.99
Myocardial infarction	−0.024	−0.13	0.174	0.38
Other heart disease	0.023	0.20	−0.632	−1.90
Stroke	−0.332^*	−2.10	−0.507	−1.41
Emphysema	−0.117	−0.67	−0.222	−0.72
High cholesterol	0.061	0.65	0.705^*	3.40
Diabetes	−0.014	−0.12	0.323	1.27
Arthritis	−0.036	−0.41	0.132	0.71
Asthma	−0.283^*	−2.92	−0.324	−1.60
Patient-provider communication
USC asks about other treatments	0.145	1.60	−0.119	−0.58
USC shows respect for treatments	0.040	0.46	0.127	0.64
USC asks person to help decide	−0.060	−0.67	0.205	1.08
USC explains options to person	−0.146	−1.08	−0.332	−0.94
USC speaks language or provides interpreter services	−0.350	−0.88	−2.130^*	−2.62
Access
Transportation to USC
Is driven	−0.016	−0.14	0.228	0.96
Public transportation	0.190	1.11	0.081	0.25
Walks or other	−0.183	−0.76	0.728	1.50
Time to USC
15 to 30 minutes	−0.073	−0.97	−0.196	−1.05
31 to 60 minutes	−0.023	−0.18	0.404	1.16
>60 minutes	0.296	1.29	1.014^*	2.53
USC has office hours on nights and weekends	0.045	0.56	0.307	1.91
Difficulty getting to USC	0.265^*	2.03	−0.164	−0.61
Difficulty in contacting USC by phone	0.113	1.22	−0.313	−1.24
Difficulty in contacting USC after hours	0.163^*	2.04	0.390^*	2.01

↵* P < .05.
MSA, metropolitan statistical area; USC, usual source of care.