ABSTRACT
Panel data models Linear models With the exception of duration analysis, all of the models described so far have been applied to a single cross-section survey, where each individual is observed only once. With panel data a longitudinal element is added to the data and there are repeated measurements for each individual observation. Panel data are closely related to multilevel data where observations are grouped within organisations or geographic areas: for example, a survey of patients, within specialties, within hospitals. Multilevel models have a similar structure to models for panel data and are not discussed here (see Further reading).
