Cross-cultural studies, sometimes called holocultural studies or comparative studies, is a specialization in anthropology and sister sciences (sociology, psychology, economics, political science) that uses field data from many societies to examine the scope of human behavior and test hypotheses about human behavior and culture. Cross-cultural studies is the third form of cross-cultural comparisons. The first is comparison of case studies, the second is controlled comparison among variants of a common derivation, and the third is comparison within a sample of cases. Unlike comparative studies, which examines similar characteristics of a few societies, cross-cultural studies uses a sufficiently large sample so that statistical analysis can be made to show relationships or lack of relationships between the traits in question. These studies are surveys of ethnographic data.