Invariance or “measurement equivalence” testing is often seen as a prerequisite for the comparison of groups, and performing tests of the equality of measurement parameters across groups is now standard practice in a wide range of research areas. The reasoning behind such tests is that substantive conclusions of interest might be affected if measurement parameters are not equal across groups.
We propose instead to directly examine the change in the substantive parameters of interest that would occur if misspecified invariance restrictions were freed. The δ_a statistic is suggested for this purpose. Its accuracy as an approximation to the change in substantive parameters of interest when freeing an equality restriction turns out to be adequate. We apply the proposed procedure to a complex published study where invariance testing was performed. This leads to different conclusions than had been reached originally by the authors, demonstrating the usefulness of our approach.
Presented by:
Daniel Oberski (University of Tilburg)
Date & time:
October 22, 2012 3:00 pm
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