Small Area Analysis and the Challenge of Practice Variation

  • John WennbergEmail author
  • Klim McPherson
  • David Goodman
Living reference work entry
Part of the Health Services Research book series (HEALTHSR)


The study of variations has challenged long-standing theories that the utilization of medical services is primarily determined by the incidence of illness, the constraints of medical science, or patient preferences. This chapter traces the development of empirical research in small area variation in the United States, England, and other countries and the concurrent evolution of explanatory theories. Variations in health services are marked across every level of care – small areas, tertiary regions, and health care providers. The majority of this variation is not explained by patient differences. We categorize different sources of variation into (1) effective care, where benefits far exceed harm, (2) preference-sensitive care, where there are a variety of options for patients, each with benefits and trade-offs, and (3) supply-sensitive care, where varying supplies of health care resources lead to differences in the frequency of care, with scant evidence that more services benefit patients. Each of these explanatory categories is linked to specific clinical and policy remedies that, if implemented, would significantly improve health care.


Practice Variation Benign Prostatic Hypertrophy Medical Opinion Surgical Signature Medicare Spending 
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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • John Wennberg
    • 1
    Email author
  • Klim McPherson
    • 2
    • 3
  • David Goodman
    • 4
    • 5
    • 6
    • 7
  1. 1.The Dartmouth Institute for Health Policy and Clinical PracticeLebanonUSA
  2. 2.Nuffield Department of Obstetrics and GynaecologyNew CollegeOxford, OxfordshireUK
  3. 3.University of OxfordOxfordUK
  4. 4.The Dartmouth Institute for Health Policy and Clinical PracticeLebanonUSA
  5. 5.Department of PediatricsDartmouth Hitchcock Medical CenterLebanonUSA
  6. 6.Department of Community and Family MedicineDartmouth Hitchcock Medical CenterLebanonUSA
  7. 7.Geisel School of Medicine at DartmouthHanoverUSA

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