title: Longitudinal construct validity: establishment of clinical meaning in patient evaluative instruments.
abstract: OBJECTIVE
  Although widely used and reported in research for the evaluation of groups, measures of health status and health-related quality of life have had little application in clinical practice for the assessment of individual patients. One of the principal barriers is the demonstration that these measures add clinically significant information to measures of function or symptoms alone. Here, we review the methods for evaluation of construct validity in longitudinal studies and make recommendations for nomenclature, reporting of study results, and future research agenda.
  
  
  METHODS
  Analytical review.
  
  
  RESULTS
  The terms "sensitivity" and "responsiveness" have been used interchangeably, and there are few studies that evaluate the extent to which health status or health-related quality-of life measures capture clinically important changes ("responsiveness"). Current methods of evaluating responsiveness are not standardized or evaluated. Approaches for the assessment of a clinically significant or meaningful change are described; rather than normative information, however, standardized transition questions are proposed. They would be reported routinely and as separate axes of description to capture individual perceptions.
  
  
  CONCLUSIONS
  Research in methods to assess the subject's evaluation of the importance and magnitude of a measured change are critical if health status and health-related quality-of-life measures are to have an impact on patient care.
authors.affiliation: Department of Medicine, Harvard Medical School, Robert B. Brigham Multipurpose Arthritis and Musculoskeletal Diseases Center, Brigham & Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Liang
mesh_terms: D006302:Health Services Research / Q000379:methods; D006305:Health Status Indicators; D006801:Humans; D008137:Longitudinal Studies; D017063:Outcome Assessment, Health Care / Q000379:methods; D011788:Quality of Life; D015203:Reproducibility of Results; D012107:Research Design; D012647:Self-Assessment