Durkheim analyzed suicide rates in the late 19th century and found they varied between religious and social groups. He identified 4 types of suicide based on levels of social integration and regulation: egoistic, altruistic, anomic, and fatalistic. While influential, Durkheim's work was criticized for making inferences about individuals based on aggregate data and overlooking reliability issues with official suicide statistics. His concept of social integration influencing suicide was also criticized as vague.