Consistency of extreme response style and non-extreme response style across traits

The consistency of extreme response style (ERS) and non-extreme response style (NERS) across the latent variables assessed in an instrument is investigated. Analyses were conducted on several PISA 2006 attitude scales and the German NEO-PI-R. First, a mixed partial credit model (PCM) and a constrained mixed PCM were compared regarding model fit. If the constrained mixed PCM fit better, latent classes differed only in their response styles but not in the latent variable. For scales where this was the case, participants’ membership to NERS or ERS on each scale was entered into a latent class analysis (LCA). For both instruments, this second order LCA revealed that the response style was consistent for the majority of the participants across latent variables.