The severity of bias in respondents' self-reports due to acquiescence response style (ARS) and extreme response style (ERS) depends strongly on how consistent these response styles are over the course of a questionnaire. In the literature, different alternative hypotheses on response style (in)consistency circulate. Therefore, nine alternative models are derived and fitted to secondary and primary data. It is found that response styles are best modeled as a tau-equivalent factor complemented with a time-invariant autoregressive effect. This means that ARS and ERS are largely but not completely consistent over the course of a questionnaire, a finding that has important implications for response style measurement and correction. (Contains 4 notes, 4 tables and 3 figures.)