minimal disruption. In his presentation, Bertozzi also drew on evidence from randomized controlled trials. Speaker Field-Nguer pointed out that nonrandom selection of sites has the potential to limit or weaken a study. Workshop participant De Lay discussed some of the potential problems with impracticality of randomization.
Several workshop participants stressed the highly contextual nature of change when comparing across contexts. Evaluations that are centrally coordinated to permit comparison of variables across contexts, while allowing some flexibility in indicator design at the local level, are optimal, suggested speaker Glenzer. Interventions that are successful in one country are not necessarily transferable to another country, noted workshop speaker Stoneburner. Examples provided by Stoneburner and speakers Latkin, Garnett, and Pulerwitz supported this statement. In some cases, factors independent of an explicit program intervention can have an influence on change. In other cases, change in behavior does not always lead to a change in the pattern of the HIV/AIDS epidemic, and changes in the pattern of the epidemic cannot always be translated to a change in behavior. Close engagement of the scientific community in evaluation, urged speaker Latkin, can help to assess the likelihood of transferability of effective programs to other settings.