title: Methodological considerations--an attempt to use treatment outcomes to validate a classification system for back problems: a critical analysis of a quasi-experiment.
authors.affiliation: Holland Associates, 9226 Milburn Loop SE, Olympia, WA 98513, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Holland
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Bigos
mesh_terms: D006801:Humans; D017116:Low Back Pain / Q000145:classification* / Q000534:rehabilitation*; D016896:Treatment Outcome; D054928:Validation Studies as Topic