Caplan L S, Lane D S, Grimson R
Department of Preventive Medicine, State University of New York at Stony Brook 11794-8036, USA.
Prev Med. 1995 Nov;24(6):553-6. doi: 10.1006/pmed.1995.1088.
The method used to select a study sample is a key element in designing a research protocol. This article explores two of the more common methods used, focusing on the relative advantages and disadvantages of each one.
Both cohort and repeated, independent cross-sectional surveys were conducted in each of 3 years (1988-1990) in the Awareness of Breast Cancer Screening Project to follow changing breast cancer screening rates among a population of women 50-75 years of age on Long Island, New York.
Both survey methods revealed statistically significant increases in self-reports of mammography use. The cohort and repeated cross-sectional survey sample responses to questions concerning knowledge, attitudes, and behavior regarding breast cancer screening were comparable. An educational effect of the baseline survey itself on the cohort was not seen.
Each of the two survey methods has advantages and disadvantages with respect to the other. The cohort method permits examination of changes in the same individual over time and is less costly and less time-consuming to perform. On the other hand, the cross-sectional method does not suffer from cumulative losses in respondents with repeated surveys and better reflects the changing community. The study findings can be used to guide the selection of an appropriate survey methodology for monitoring breast cancer screening practices in other settings.
选择研究样本的方法是设计研究方案的关键要素。本文探讨了两种较为常用的方法，重点关注每种方法的相对优缺点。
在1988 - 1990年的3年时间里，每年都在乳腺癌筛查意识项目中开展队列研究和重复独立横断面调查，以跟踪纽约长岛50 - 75岁女性群体中乳腺癌筛查率的变化情况。
两种调查方法均显示，乳房X光检查使用情况的自我报告有统计学上的显著增加。队列研究和重复横断面调查样本对有关乳腺癌筛查的知识、态度和行为问题的回答具有可比性。未发现基线调查本身对队列研究对象有教育效果。
两种调查方法各有优缺点。队列研究方法允许随时间检查同一个体的变化，实施成本较低且耗时较少。另一方面，横断面方法不会因重复调查导致应答者累积流失，能更好地反映社区的变化情况。研究结果可用于指导选择合适的调查方法，以监测其他环境下的乳腺癌筛查实践。
