The multilevel regression model

The multilevel regression model Social and behavioral research often concerns data that have a hierarchical structure, with individuals nested within groups. In multilevel analysis, such data structures are viewed as a multistage sample from a hierarchical population. For example, in educational research we may have a sample of schools, and within each school a sample of pupils. This results in a data set consisting of pupil data (e.g. socioeconomic status, intelligence, school career) and school data (e.g. school size, denomination, but also aggregated pupil variables such as mean socioeconomic status). In this chapter, the generic term ‘multilevel’ is used to refer to analysis models for hierarchically structured data, with variables defined at all levels of the hierarchy. Typically, the research problem includes hypotheses of relationships between variables defined at different levels of the hierarchy.