In the enormous collection of cross-cultural data that have been published during the last few decades it is difficult to perceive patterns. There is a clear need for systematizing the vast amount of cross-cultural studies and for developing models that explain cross-cultural differences in psychology. Two methods of cross-cultural meta-analysis can be distinguished. First, the instrument-based method of comparing data for one instrument across countries is suitable for instruments which have been administered in many countries. Second, a domain-based meta-analysis used a thematic domain from which culture-comparative studies are sampled instead of one specific instrument or method.