Evangeli Michael, Kafaar Zuhayr, Kagee Ashraf, Swartz Leslie, Bullemor-Day Philippa
Department of Psychology, Royal Holloway University of London, London, UK.
AIDS Care. 2013;25(7):910-4. doi: 10.1080/09540121.2012.748163. Epub 2012 Dec 7.
It is vital that enough participants are willing to participate in clinical trials to test HIV vaccines adequately. It is, therefore, necessary to explore what affects peoples' willingness to participate (WTP) in such trials. Studies have only examined individual factors associated with WTP and not the effect of messages about trial participation on potential participants (e.g., whether losses or gains are emphasized, or whether the outcome is certain or uncertain). This study explores whether the effects of message framing on WTP in a hypothetical HIV vaccine trial are consistent with Prospect Theory. This theory suggests that people are fundamentally risk averse and that (1) under conditions of low risk and high certainty, gain-framed messages will be influential (2) under conditions of high risk and low certainty, loss-framed messages will be influential. This cross-sectional study recruited 283 HIV-negative students from a South African university who were given a questionnaire that contained matched certain gain-framed, certain loss-framed, uncertain gain-framed, and uncertain loss-framed statements based on common barriers and facilitators of WTP. Participants were asked to rate how likely each statement was to result in their participation in a hypothetical preventative HIV vaccine trial. Consistent with Prospect Theory predictions, for certain outcomes, gain-framed messages were more likely to result in WTP than loss-framed messages. Inconsistent with predictions, loss-framed message were not more likely to be related to WTP for uncertain outcomes than gain-framed messages. Older students were less likely to express their WTP across the different message frames. Recruitment for HIV vaccine trials should pay attention to how messages about the trial are presented to potential participants.
至关重要的是，要有足够多的参与者愿意参与临床试验，以便充分测试HIV疫苗。因此，有必要探究是什么影响了人们参与此类试验的意愿（WTP）。此前的研究仅考察了与参与意愿相关的个体因素，而未考察关于试验参与的信息对潜在参与者的影响（例如，是否强调损失或收益，或者结果是确定还是不确定）。本研究探讨了在假设的HIV疫苗试验中，信息框架对参与意愿的影响是否与前景理论一致。该理论表明，人们本质上是厌恶风险的，并且（1）在低风险和高确定性的情况下，收益框架信息将具有影响力；（2）在高风险和低确定性的情况下，损失框架信息将具有影响力。这项横断面研究从南非一所大学招募了283名HIV阴性学生，他们被给予一份问卷，其中包含基于参与意愿的常见障碍和促进因素而匹配的确定性收益框架、确定性损失框架、不确定性收益框架和不确定性损失框架的陈述。参与者被要求对每条陈述导致他们参与假设的预防性HIV疫苗试验的可能性进行评分。与前景理论的预测一致，对于确定性结果，收益框架信息比损失框架信息更有可能导致参与意愿。与预测不一致的是，对于不确定性结果，损失框架信息与参与意愿的关联并不比收益框架信息更显著。年龄较大的学生在不同信息框架下表达参与意愿的可能性较小。HIV疫苗试验的招募工作应注意向潜在参与者呈现试验信息的方式。
