Stone Arthur A, Broderick Joan E, Schwartz Joseph E, Schwarz Norbert
Department of Psychiatry and Behavioral Science, Stony Brook University, Stony Brook, New York 11994-8790, USA.
Med Care. 2008 Jul;46(7):662-7. doi: 10.1097/MLR.0b013e3181789387.
Survey self-reports of health status, symptoms (pain and fatigue), and life satisfaction often serve as outcomes in clinical trials. Prior studies have shown, however, that such reports can be subject to context effects, which could threaten their validity.
We examined the impact of 2 context effects: the effect of the reporting period associated with a question (No Period Specified; Last Month; Right Now) and the effect of whom the respondent compared themselves to in answering a question (None Specified; Compared with Others in the US; Compared with 20-Year-Olds).
One thousand four hundred seventy-one community adults aged 20 through 70 years, who were members of an internet panel, responded to 1 of 9 questionnaires formed by crossing the 2 context variables. A significant effect of Reporting Period was observed indicating that higher levels of Pain and Fatigue were associated with the 1-Month reporting period. When no reporting period was specified, symptom levels were equivalent to the Right Now levels of symptoms. Reporting Period had no effect on the other outcomes. Educational level did not interact with these main effects, with 1 exception. None of the predicted effects were found for Comparison Group, although Pain was significantly associated with this factor.
Reporting period in survey questions is a factor that influences responses and should be considered by survey researchers in their study designs.
健康状况、症状（疼痛和疲劳）及生活满意度的调查自我报告常作为临床试验的结果。然而，先前的研究表明，此类报告可能会受到情境效应的影响，这可能会威胁到其有效性。
我们研究了两种情境效应的影响：与问题相关的报告期效应（未指定时期；上个月；此刻）以及回答问题时被调查者将自己与谁进行比较的效应（未指定；与美国其他人比较；与20岁的人比较）。
1471名年龄在20至70岁之间的社区成年人，他们是一个互联网小组的成员，对通过交叉这两个情境变量形成的9份问卷中的1份做出了回应。观察到报告期有显著效应，表明疼痛和疲劳程度较高与1个月的报告期相关。当未指定报告期时，症状水平与此刻的症状水平相当。报告期对其他结果没有影响。教育水平与这些主要效应没有相互作用，但有一个例外。比较组未发现任何预测效应，尽管疼痛与该因素显著相关。
调查问卷中的报告期是影响回答的一个因素，调查研究人员在研究设计中应予以考虑。
