This study explores the acquiescent response style (ARS) among respondents in the Czech Republic. To analyse ARS, confirmatory factor analysis (CFA) was employed and the response style (RS) was modelled as a latent variable. The RS factor in the CFA model must be validated by its relationship to education and age, i.e. proxies of cognitive ability. The two studies presented in this article use large amount of data as all available balanced batteries of items were analysed. In Study 1, the RS factor showed no correlation with age/education in most of the models. Study 2 employed additional measures of cognitive ability and education and confirmed the overall absence of the relationship. Author concludes that the modelled RS factor then cannot be considered the ARS and deduces that the most likely explanation of the identified systematic error variance is the respondents' carelessness manifested by automatically choosing the extreme agreement, or choosing the first presented answer as a result of memory effect.