Beginning July 15, 1996 a total of 794 participants were recruited and randomly assigned to one of the four groups. In addition to assessing the impact of the intervention, analyses compared the relative importance of the hypothesized influencing and mediating factors on behavior. Cost-effectiveness analyses were also conducted. During the later stages of the study, clinic staff from throughout Los Angeles County were trained and encouraged to integrate the strategies that appeared to be effective into their clinic setting.