title: Comparing three preprocessing strategies for longitudinal data. An example in functional outcomes research.
abstract: Longitudinal monitoring of individual patient data is becoming routine in physician office practice. This study compares three different methods for evaluating clinical outcomes for individual patients: raw change score analysis versus normative and ipsative statistical analyses. Two discrete samples of intermittent claudication patients making vascular surgery office visits--drawn from interventional management versus stable, routinely followed control groups--were tested four times using both generic and disease-specific functional status measures. Results indicated that the ipsative method was most consistent with several different types of a priori hypotheses that are often evaluated in analysis of repeated measures data.
authors.affiliation: Division of General Internal Medicine, Northwestern University Medical School, Chicago, IL 60611, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Yarnold
authors.forename: J
authors.initials: J
authors.lastname: Feinglass
authors.forename: W J
authors.initials: WJ
authors.lastname: McCarthy
authors.forename: G J
authors.initials: GJ
authors.lastname: Martin
mesh_terms: D005069:Evaluation Studies as Topic; D006801:Humans; D008137:Longitudinal Studies; D017063:Outcome Assessment, Health Care / Q000379:methods*; D016491:Peripheral Vascular Diseases / Q000628:therapy; D013223:Statistics as Topic