Stuart Gretchen S, Grimes David A
Department of Obstetrics and Gynecology, University of North Carolina School of Medicine Chapel Hill, NC 27599-7030, USA.
Contraception. 2009 Aug;80(2):108-12. doi: 10.1016/j.contraception.2009.02.009. Epub 2009 Apr 22.
Studies on family planning methods traditionally have relied on self-reports of unknown validity and reproducibility. Social desirability bias, a type of information bias, occurs when study participants respond inaccurately - but in ways that will be viewed favorably by others. Several lines of evidence reveal that this bias can be powerful in sexual matters, including reports of coitus, use of contraceptives and induced abortion. For example, studies using vaginal prostate-specific antigen testing reveal underreporting of unprotected coitus and overreporting of barrier contraceptive use. Medication Event Monitoring System studies, which electronically record the time of pill dispensing from a bottle or pack, indicate widespread exaggeration of adherence to pill-taking regimens, including oral contraceptives. Comparisons of provider data and self-reports of induced abortions reveal extensive underreporting of induced abortion. Reliance on self-reported data underestimates contraceptive efficacy. Although techniques to minimize this bias exist, they are infrequently used in family planning studies. Greater skepticism about self-reports and more objective means of documenting coitus and contraceptive use are needed if contraceptive efficacy is to be accurately measured.
传统上，计划生育方法的研究依赖于有效性和可重复性未知的自我报告。社会期望偏差是信息偏差的一种，当研究参与者回答不准确，但以他人会认为有利的方式回答时就会出现这种偏差。几条证据表明，这种偏差在性方面可能很强大，包括性交报告、避孕药具的使用和人工流产。例如，使用阴道前列腺特异性抗原检测的研究表明，未保护性交的报告不足，屏障避孕法使用的报告过度。药物事件监测系统研究通过电子方式记录从瓶子或包装中取出药丸的时间，结果表明人们普遍夸大了对服药方案的依从性，包括口服避孕药。提供者数据与人工流产自我报告的比较显示人工流产报告大量不足。依赖自我报告的数据会低估避孕效果。虽然存在尽量减少这种偏差的技术，但它们在计划生育研究中很少使用。如果要准确衡量避孕效果，就需要对自我报告持更大的怀疑态度，并采用更客观的方法来记录性交和避孕措施的使用情况。
