Cognitive construct measurement in small samples of younger and older adults: an example of verbal working memory

An important issue in experimental aging research is the accurate measurement of cognitive constructs, particularly in small-sample studies. Latent variable modeling approaches to assessing age-based construct similarity are difficult to implement in smaller-scale studies, which tend to have small samples and measurement of a single construct. We discuss factor score comparison methods for assessing age-based construct similarity that may be more appropriate for small-scale studies. We then examine these methods for a series of single-factor models of verbal working memory (VWM) based on data from three separate studies in which small samples of younger and older adults' completed VWM-based tasks. Our single-factor models accounted well for the associations among the sets of VWM tasks. This construct was also measured well across age groups and different samples. Our analyses suggest that factor score comparison methods may be useful for small-scale studies that require assessment of age-based measurement similarity in cognitive constructs.