The movement or shifting of membership between or within social classes by individuals or by groups.

A stratum of people with similar position and prestige; includes social stratification. Social class is measured by criteria such as education, occupation, and income.

Social and economic factors that characterize the individual or group within the social structure.

Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.

Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.

Any behavior caused by or affecting another individual, usually of the same species.