Scholars and researchers of international education frequently use data from large-scale cross-national studies such as the Programme for International Student Assessment (PISA), a periodic international assessment consisting of cognitive, attitudinal, and sociodemographic measures conducted by the Organisation for Economic Co-operation and Development (OECD). Several components of PISA contain conventional Likert-type scales of psychological attitudes which are administered to students, parents, and school personnel in many nations. Secondary analysts of these attitudinal data, however, generally ignore the issue of cultural differences in response style or scale usage heterogeneity, leading to descriptive statistics and inferences that may be biased and misleading. In this paper I explore this issue several ways and illustrate the extent, consequences, and some possible solutions using data from PISA 2006.