A COMPARISON OF THE FACTOR STRUCTURE OF PROCESSING SPEED FOR YOUNGER AND OLDER ADULTS - TESTING THE ASSUMPTION OF MEASUREMENT EQUIVALENCE ACROSS AGE-GROUPS

The purpose of this study was to investigate measurement equivalence o f processing speed measures for different age groups. A structural equ ation modeling approach was used to investigate a measurement model an d the factorial invariance between younger and older adults on speed m easures. The analyses concurrently examined whether speed-related abil ities dedifferentiate with increasing age. One hundred and forty-four younger and 105 older adults completed 9 measures designed to assess m otor speed, alphanumeric speed, and geometric speed. Results indicated that although the number of factors and the factor loadings were inva riant across age groups, the interfactor correlations, the variance-co variance matrices, and the unique variances differed across groups. Fu rthermore, a second-order speed factor seemed to explain much of the v ariance in the 3 first-order factors, although this higher order facto r accounted for slightly more variance among the older group than amon g the younger group. The results suggest that there is sufficient evid ence of measurement equivalence on the current speed measures across t he 2 adult age groups and, in addition, provide evidence of dedifferen tiation.