study of larger groups with the aim of discovering norms, universal principles of 'laws' of behaviour.
General laws provide a ‘benchmark’ against which people can be compared, classified and measured, where future behaviour can be predicted and/or controlled.
The approach is associated with ‘scientific’ methods, such as experiments, usually involving large numbers of people to establish ways in which people are similar.
Classifying people into groups based on characteristics, attitudes or behaviour, led to the development of the ICD-10 and DSM-5.