The aim of this study is to contribute to a better understanding of extreme response style in cross-cultural research by integrating quantitative and qualitative evidence in a mixed methods design. In the quantitative phase, indexes of extreme response style, derived from quality of life measures from different international studies, were compared between Spain and the Netherlands. Results indicated that extreme responding was more common among Spanish than among Dutch in endorsement of items, but that the opposite was found for frequency scales including never as a response anchor. In the qualitative phase, cognitive interviews were conducted with 25 participants in each country. The integration of quantitative results and qualitative findings suggests that country differences in extreme response style may stem from various sources, including the more independent evaluation of each item by Dutch, the stronger connotations of never for Spanish and stronger emotions triggered by specific topics such as work satisfaction that was more strongly associated with insecurity for Spanish. It is concluded that the integration of quantitative and qualitative evidence can help to understand cross-cultural similarities and differences in extreme response style.
