title: An example of using mixed models and PROC MIXED for longitudinal data.
abstract: Longitudinal data, or data that are repeated measurements on various subjects across time, are commonplace in biostatistical studies. The general linear mixed model is a useful statistical tool for analyzing such data and drawing meaningful inferences about them. This paper discusses some of the most common mixed models and fits them to a prototypical example involving repeated measures on blood pressure. Computer implementation is via the MIXED procedure in the SAS System, and code descriptions and output interpretations accompany the example.
authors.affiliation: SAS Institute Inc., Cary, North Carolina 27513, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Wolfinger
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods; D008137:Longitudinal Studies; D015233:Models, Statistical; D012984:Software