Negotiation skill is measured by (4-point Likert scale) assessor ratings of the extent of 4 basic negotiation skills demonstrated in participants’ completion of sexual risk vignettes. These skills are: assertiveness (in demanding safer sex from partners); informativeness (about the need for safer sex); ability to anticipate high-risk situations (demonstrated by mention of carrying condoms); and implementation (of safer sex skills). A total skill score can be obtained by summing these. A count of number of alternative solutions is generated. A count of number of obstacles identified is generated.