This study examined the impact of two questionnaire characteristics, scale position and questionnaire length, on the prevalence of random responders in the TIMSS 2015 eighth-grade student questionnaire. While there was no support for an absolute effect of questionnaire length, we did find a positive effect for scale position, with an increase of…

The current simulation study examined the effects of Item Parameter Drift (IPD) occurring in a short scale on parameter estimates in multilevel models where scores from a scale were employed as a time-varying predictor to account for outcome scores. Five factors, including three decisions about IPD, were considered for simulation conditions. It…