Scoring the SF-36 in Orthopaedics: A Brief Guide.

The Short Form-36 (SF-36) is the most widely used health-related quality-of-life measure in research to date. There are currently two sources for the SF-36 and scoring instructions: licensing them from Optum, Inc., or obtaining them from publicly available documentation from the RAND Corporation. The SF-36 yields eight scale scores and two summary scores. The physical component summary (PCS) and mental component summary (MCS) scores were derived using an orthogonal-factor analytic model that forced the PCS and MCS to be uncorrelated, and it has been shown to contribute to an inflation of the MCS in patients with substantial physical disability. Oblique scoring can reduce this inflation of the MCS in orthopaedic studies. Spreadsheets to score the SF-36, along with a copy of the questionnaire, are provided.