Modeling Count Outcomes from HIV Risk Reduction Interventions: A Comparison of Competing Statistical Models for Count Responses

Table 1

Distribution of outcomes.

Outcome	Zero (percentage)	Mean	Variance
All vaginal sex episodes
3 months	16.35	12.00	183.53
6 months	17.90	12.01	214.77
12 months	16.28	15.26	326.26
Unprotected vaginal sex with steady partners
3 months	43.67	4.90	70.01
6 months	42.38	6.00	108.70
12 months	33.69	7.15	112.04
Unprotected vaginal sex with other partners
3 month	87.69	0.32	1.31
6 months	89.61	0.27	1.15
12 months	86.50	0.39	1.69
Any unprotected vaginal sex with steady or other partners
3 months	39.47	4.80	52.65
6 months	39.67	5.60	72.99
12 months	29.44	7.55	122.98