Level III Evidence: A Case-Control Study

  • Andrew D. LynchEmail author
  • Adam J. Popchak
  • James J. Irrgang


Case-control studies are used to retrospectively determine the role of an exposure in the etiology of an outcome or condition of interest that is rare or takes a long time to develop. Because of the retrospective nature, case-control studies can be completed relatively quickly and at a smaller cost than a prospective observational study. However, the retrospective nature may introduce multiple types of bias into the data set, and results must be considered in light of the limitations of the retrospective study. This chapter outlines approaches to selecting cases and controls, designing studies to minimize bias, and basic approaches to statistical analysis.


  1. 1.
    Bhandari M, Morshed S, Tornetta P 3rd, Schemitsch EH. Design, conduct, and interpretation of nonrandomized orthopaedic studies: a practical approach. (All) evidence matters. J Bone Joint Surg Am. 2009;91(Suppl 3):1. Scholar
  2. 2.
    Busse JW, Obremskey WT. Principles of designing an orthopaedic case-control study. J Bone Joint Surg Am. 2009;91(Suppl 3):15–20. Scholar
  3. 3.
    Gilbert R, Martin RM, Donovan J, Lane JA, Hamdy F, Neal DE, Metcalfe C. Misclassification of outcome in case-control studies: methods for sensitivity analysis. Stat Methods Med Res. 2016;25:2377–93. Scholar
  4. 4.
    Joseph L, Belisle P. Bayesian sample size determination for case-control studies when exposure may be misclassified. Am J Epidemiol. 2013;178:1673–9. Scholar
  5. 5.
    Mayo NE, Goldberg MS. When is a case-control study a case-control study? J Rehabil Med. 2009;41:217–22. Scholar
  6. 6.
    Mayo NE, Goldberg MS. When is a case-control study not a case-control study? J Rehabil Med. 2009;41:209–16. Scholar
  7. 7.
    Morshed S, Tornetta P 3rd, Bhandari M. Analysis of observational studies: a guide to understanding statistical methods. J Bone Joint Surg Am. 2009;91(Suppl 3):50–60. Scholar
  8. 8.
    Nesvick CL, Thompson CJ, Boop FA, Klimo P Jr. Case-control studies in neurosurgery. J Neurosurg. 2014;121:285–96. Scholar
  9. 9.
    Portney LG, Watkins MP. Foundations of clinical research : applications to practice. 2nd ed. Upper Saddle River, NJ: Prentice Hall; 2000.Google Scholar
  10. 10.
    Sackett DL. Bias in analytic research. J Chron Dis. 1979;32:51–63. Scholar
  11. 11.
    Schulz KF, Grimes DA. Case-control studies: research in reverse. Lancet. 2002;359:431–4. Scholar
  12. 12.
    Vandenbroucke JP, et al. Strengthening the reporting of observational studies in epidemiology (STROBE): explanation and elaboration. PLoS Med. 2007;4:e297. Scholar
  13. 13.
    von Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC, Vandenbroucke JP, Initiative S. The strengthening the reporting of observational studies in epidemiology (STROBE) statement: guidelines for reporting observational studies. PLoS Med. 2007;4:e296. Scholar

Copyright information

© ISAKOS 2019

Authors and Affiliations

  • Andrew D. Lynch
    • 1
    Email author
  • Adam J. Popchak
    • 1
  • James J. Irrgang
    • 1
  1. 1.Departments of Physical Therapy and Orthopaedic SurgeryUniversity of PittsburghPittsburghUSA

Personalised recommendations