Skip to main content
SpringerLink
Log in

Measuring subjective outcomes

Rethinking reliability and validity

  • From Research To Practice
  • Published:
Journal of General Internal Medicine Aims and scope Submit manuscript

Abstract

Reliability and validity are criteria used to assess metric adequacy and are typically quantified by correlation coefficients. Reliability is described as the extent to which repeated measurements yield consistent results. Validity is described as the extent to which a measure actually measures what it purports to measure. These conceptualizations are less useful when applied to measures of subjective outcomes because they do not convey other influences that “drive” correlation coefficients. Consistency is a manifestation of a reliable instrument but does not ensure that an instrument is reliable. Establishing the validity of an instrument is a complex process that is heavily dependent on an investigator’s hypothesis. Hence, validity coefficients may be more a reflection of hypothesis adequacy than of the extent to which instruments measure what they purport to measure. Appreciating how coefficients are influenced will better enable clinicians to assess the adequacy of subjective outcome measures.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. McDowell I, Newell C. Measuring Health: A Guide to Rating Scales and Questionnaires. 2nd ed. Oxford, England: Oxford University Press; 1996.

    Google Scholar 

  2. Nunnally JC, Bernstein IH. Psychometric Theory. 3rd ed. New York, NY: McGraw-Hill; 1994.

    Google Scholar 

  3. Bergner M. Measurement of health status. Med Care 1985;23:696–704.

    Article  PubMed  CAS  Google Scholar 

  4. Quality of life and clinical trials. Lancet. 1995;346:1–2. Editorial.

    Google Scholar 

  5. Stewart AL, Greenfield S, Hays RD, et al. Functional status and well-being of patients with chronic conditions: results from the Medical Outcomes Study. JAMA. 1989;262:907–13.

    Article  PubMed  CAS  Google Scholar 

  6. Kessler RC, Mroczek DK. Measuring the effects of medical interventions. Med Care. 1995;33:AS109–19.

    PubMed  CAS  Google Scholar 

  7. Testa MA, Simpson DC. Assessment of quality-of-life outcomes. N Engl J Med. 1994;334:835–40.

    Article  Google Scholar 

  8. Hulley SB, Cummings SR. Designing Clinical Research. Baltimore, Md: Williams & Wilkins; 1988:31–41.

    Google Scholar 

  9. Royce A, Singleton J, Straits BC, Staits MM. Approaches to Social Research. 2nd ed. New York, NY: Oxford University Press; 1993:114–30.

    Google Scholar 

  10. Fletcher RH, Fletcher SW, Wagner EH. Clinical Epidemiology: The Essentials. 3rd ed. Baltimore, Md: Williams & Wilkins; 1996:22–4.

    Google Scholar 

  11. DeVellis RF. Scale Development: Theory and Applications. Applied Social Research Methods Series. Newbury Park, Calif: Sage; 1991.

    Google Scholar 

  12. McCall R. Fundamental Statistics for Behavioral Sciences. 7th ed. Pacific Grove, Calif: Brooks/Cole; 1988:151–75.

    Google Scholar 

  13. Isaac S, Michael W. Handbook in Research and Evaluation for Education and the Behavioral Sciences. 3rd ed. San Diego, Calif: EDITS; 1995:174–80.

    Google Scholar 

  14. Perrin EB, Aaronson NK, Lohr KN, et al. Instrument review criteria. Med Outcomes Trust. 1997:1–5.

  15. Sudman S, Bradburn NM. Asking questions: a practical guide to questionnaire design. In: Fiske DW, ed. Series in Social and Behavioral Sciences. San Francisco, Calif: Jossey-Bass; 1982.

    Google Scholar 

  16. Striener D, Norman G. Health measurement scales: a practical guide to their development and use. In: Striener D, Norman G, eds. 2nd ed. New York, NY: Oxford University Press; 1995:150–7.

    Google Scholar 

  17. Stewart AL, Hays RD, Ware JE. The MOS Short-Form General Health Survey: reliability and validity in a patient population. Med Care. 1988;26:724–32.

    Article  PubMed  CAS  Google Scholar 

  18. Rosenstock I, Strecher V, Becker M. Social learning theory and the health belief model. Health Educ Q. 1988;15:175–83.

    PubMed  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. the Division of Internal Medicine, Department of Medicine, Vanderbilt University, Nashville, Tenn.

    Tom A. Elasy MD, MPH

  2. Institute for Research in Social Science, University of North Carolina, Chapel Hill, N.C.

    Gary Gaddy PhD

Authors
  1. Tom A. Elasy MD, MPH
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Gary Gaddy PhD
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

From Research to Practice, a Journal series, presents articles to heighten the clinician’s awareness of research and methodology issues that have direct relevance to practice. If you wish to submit a manuscript for consideration for this series, please contact Cynthia D. Mulrow, MD, MSc, Associate Editor, at mulrowc @uthscsa.edu, or contact the Journal of General Internal Medicine at (215) 823-4471 to receive the appropriate guidelines.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Elasy, T.A., Gaddy, G. Measuring subjective outcomes. J GEN INTERN MED 13, 757–761 (1998). https://doi.org/10.1046/j.1525-1497.1998.00228.x

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1046/j.1525-1497.1998.00228.x

Key words

Search

Navigation