Relationship between network size and recruitment probability in the target population.

The relationship is shown for three men with (A) low, (B) medium, and (C) high probabilities of recruitment based on the other variables in the logistic regression model (age group, socioeconomic status, tribe, hiv status, sexual activity group, distance to the nearest interview site and participation in the last cohort round. The figure shows that the relationship is non-linear, and that network size has little effect on recruitment probability apart from for men with small network sizes.