A comparison of two time intervals for test-retest reliability of health status instruments

J Clin Epidemiol. 2003 Aug;56(8):730-5. doi: 10.1016/s0895-4356(03)00084-2.


Studies of test-retest reliability for health-related quality of life instruments have used varying intervals between test administrations. There is no evidence available to aid in the selection of the time interval between questionnaire administrations for a study of test-retest reliability for health status instruments. We compared the test-retest reliability at 2 days and 2 weeks for four knee-rating scales and the eight domains of the SF-36. Seventy patients with disorders of the knee who were in a stable state were randomly allocated to repeat the questionnaires at either 2 days or 2 weeks. There were no statistically significant differences in the test-retest reliability (intraclass correlation coefficient and limits of agreement statistics) for the two time intervals.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Athletic Injuries / physiopathology
  • Female
  • Health Status Indicators*
  • Humans
  • Knee Joint / physiopathology
  • Male
  • Middle Aged
  • Reproducibility of Results
  • Sample Size
  • Surveys and Questionnaires
  • Time Factors