Abstract
► This study examined the association between IQ scores and sample attrition. ► The analyses used data from the National Longitudinal Study of Adolescent Health. ► Findings revealed that subjects with lower IQ scores were more likely to drop out of the sample. ► Analyses revealed that dropouts had IQs that were about 4.5 points lower than non-dropouts.
Selective attrition is a potentially serious problem that can bias the findings that are generated from longitudinal samples. Although the extent to which IQ might be involved in selective attrition has been studied, the results from these studies have been decidedly mixed. The current study adds to the literature examining the link between IQ and selective attrition by examining four waves of data from the National Longitudinal Study of Adolescent Health. Analysis of these data revealed that IQ is related to attrition, with lower IQ respondents more likely to drop out of the study when compared against higher IQ respondents. The evidence suggests that dropouts score about 4.5 IQ points lower than subjects who did not drop out. Limitations of the study are noted and directions for future research are discussed.