Critics of Kinesthetic Aftereffect (KAE) recommend abandoning it as a personality measure largely because of poor test-retest reliability. Although no test can be valid if lacking true reliability, to discard a measure because of poor retest reliability is an oversimplification of validation procedures. This pitfall is exemplified here by a reexamination of KAE. KAE scores involve measures before (pretest) and after (test) aftereffect induction. Internal analysis of a KAE study showed: differential bias is present; its locus is the second session pretest; its form makes second-session pretest scores functionally more similar to first- and second-session test scores and functionally more dissimilar to first-session pretest scores. Given this second session bias, the retest correlation tells us nothing about the true reliability of a one-session KAE score. However, if a measure possesses external validity, it must to some degree show true reliability. Based upon a literature review of one-session KAE validity studies, we conclude that one session KAE scores are valid and hence show true reliability. KAE remains a promising personality measure. (22pp.)
