Fig. 1.

Procedure used to determine whether a SRD choice is safe or risky, taking into account the context of the choice. Each box in the first level of multiple alternatives in this chart describes all the alternatives participants had for a particular SRD. ‘Previously agreed to safe sex’ describes a ‘NA’ indicates a particular choice is not relevant to sexual risk-taking at all. Some choices are considered ‘risky’ merely relative to others. For instance, switching positions is not inherently risky, but if participants have not previously agreed to safe sex, it is deemed risky relative to choosing an alternative sexual activity with virtually no HIV risk.