Salthouse Timothy A
Department of Psychology, University of Virginia, Charlottesville.
J Gerontol B Psychol Sci Soc Sci. 2014 Jul;69(4):567-74. doi: 10.1093/geronb/gbt046. Epub 2013 Jun 2.
Identify characteristics distinguishing people who do and do not continue to participate in a longitudinal study and determine whether the longitudinal changes for people who continue are representative of the changes that would have occurred had longitudinal data been available from all of the initial participants.
Moderately large samples of returning (N = 2,082) and nonreturning (N = 1,698) participants across a wide age range (i.e., 18-97 years of age) performed a battery of cognitive tests and completed personality and mood questionnaires. Differences between the groups were examined with multiple regression analyses with age, returner status, and their interaction as predictors.
Compared with participants who did not return, returning participants at the initial occasion had higher levels of each cognitive ability and of certain personality characteristics (e.g., agreeableness and openness), but many of the differences were only apparent among adults older than 50 years of age. Importantly, there was no evidence that the longitudinal change for nonreturning participants would have been different from that among the participants who did return.
The phenomenon of selective attrition is more complex than often assumed, and it may not necessarily limit the generalizability of longitudinal comparisons.
确定区分继续参与和不再参与纵向研究的人群的特征，并确定继续参与研究的人群的纵向变化是否代表了如果所有初始参与者都能提供纵向数据时可能发生的变化。
从广泛的年龄范围（即18 - 97岁）中选取了数量适中的大量返回参与者样本（N = 2082）和未返回参与者样本（N = 1698），让他们进行一系列认知测试，并完成人格和情绪问卷。以年龄、返回者状态及其交互作用作为预测变量，通过多元回归分析来检验两组之间的差异。
与未返回的参与者相比，初始阶段返回的参与者在各项认知能力以及某些人格特征（如宜人性和开放性）方面水平更高，但许多差异仅在50岁以上的成年人中较为明显。重要的是，没有证据表明未返回参与者的纵向变化会与返回参与者的纵向变化有所不同。
选择性损耗现象比通常认为的更为复杂，它不一定会限制纵向比较的普遍性。
