Shopping surveys for retail research

Control for Omitted Variables in the Analysis of Panel and Other Longitudinal Data

“…The use of panel data has a long history in marketing research and studies using panel data may be found in most other areas of social science endeavor. There is also evidence that increasing resources are being made available for panel studies (Singer and Spilerman 1976;Daganzo and Sheffi 1979;Guy, Wrigley, and O'Brien 1983). Nevertheless, the researcher wishing to analyze longitudinal data has to confront inferential problems for which the standard statistical literature provides little guidance.…”