Guttman scale analysis of longitudinal data: a methodology and drug use applications

Traditional Guttman scalogram analysis is limited to evaluating item order cross-sectionally. This paper describes a new methodology, Longitudinal Scalogram Analysis (LSA), that is a direct extension of cross-sectional scalogram analysis to longitudinal data. Example applications of the LSA method to drug use data are provided. The benefits of LSA relative to cross-sectional methods for drug use analysis are discussed.