The SF-36, short for 36-Item Short Form Health Survey, measures perceived health across eight scales scored from 0 to 100. It is free to use from its publisher, it has no legitimate global score, and three of its scales hit a ceiling. The profile fills in below.
Three scales hit a ceiling: both role scales and social functioning. A patient already at 100 on one of them will not be able to show any improvement there. The detail is below.
Figures taken from the studies listed at the end of this page, every value carrying its source where it is written. The questionnaire itself is not reproduced here.
What the SF-36 measures
The SF-36 measures perceived health, not a disease. Published in 1992 by Ware and Sherbourne as part of the Medical Outcomes Study, it covers thirty-six items across eight concepts: physical functioning, role limitations due to physical health, bodily pain, general health perceptions, vitality, social functioning, role limitations due to emotional problems and mental health.
Its strength is being generic. It compares chronic low back pain with heart failure, which no region-specific scale can do, and that is why it appears in almost every large cohort.
Its reliability was tested in 3,445 patients and replicated across 24 subgroups: it runs from 0.65 to 0.94 depending on the scale, with a median of 0.85. Item completion runs from 88 to 95 %, somewhat lower among older people and those with less education.
Eight scales, no global score
The SF-36 does not yield one score out of 100. It yields eight scores out of 100, and averaging them is the most widespread misreading of all.
The 1993 validity study explains why. Physical functioning and role-physical best distinguish degrees of medical severity; mental health and role-emotional best distinguish psychiatric disorders. But social functioning, vitality and general health measure both at once: adding them up mixes dimensions the authors took care to show are not interchangeable.
Two summary scores do exist, physical and mental, but computing them rests on weightings that cannot be derived from the eight scales. A spreadsheet that recomputes them by hand gets them wrong; the profile of the eight scales, by contrast, reads with nothing but the eight values.
Three scales that hit a ceiling
This is the limit the SF-36 has carried since its validation, and the one that matters most in rehabilitation.
The 1994 study records noteworthy ceiling effects on both role scales and on social functioning. In other words, a sizeable share of respondents already scores the maximum there, and those three scales can then no longer rise, whatever the real benefit of treatment.
The 2021 meta-analysis in cardiac and pulmonary rehabilitation follows the reasoning through. The role scales explain only 24 to 27 % of the variance in change there, and the authors conclude that the SF-36 is not suited as a pre- to post-programme measure in those two fields. The minimum clinically important difference, measured in 310 patients operated on for a musculoskeletal tumour, settles around 5 points for both summary scores.
| Scale | What it best distinguishes | Ceiling effect |
|---|---|---|
| Physical functioning | medical severity | no |
| Role limitations, physical health | medical severity | yes |
| Bodily pain | mostly the physical | no |
| General health perceptions | physical and mental | no |
| Vitality | physical and mental | no |
| Social functioning | physical and mental | yes |
| Role limitations, emotional problems | psychiatric disorders | yes |
| Mental health | psychiatric disorders | no |
Free in English, another matter in French
The original questionnaire is free. Its publisher writes that its surveys are public documents, that it neither charges nor requires permission, and explicitly grants permission to use it, with no further written permission needed.
Two conditions come with that permission: any change must be identified as made by whoever made it, and printing as well as distribution must carry a credit line naming the publisher and the Medical Outcomes Study. The user also takes responsibility for any translation.
That is precisely where French changes things. The permission covers the English questionnaire; the validated French version is a distinct work, published in 1998 by Leplège et al. after a first rapid translation tested in 1995 in 1,007 Geneva residents. Translating the items yourself would amount to manufacturing an unvalidated French version, which is exactly the mistake this page warns against.
Why this page does not display the questionnaire
It is not a matter of rights: the publisher of the English questionnaire explicitly authorises its use, with no further written permission, provided its credit line is carried. It is a matter of language. The validated French version is a distinct work, and publishing a home-made translation of the thirty-six items would put into circulation a version for which none of the measurement properties quoted here would be guaranteed. The tool on this page therefore scores the eight scales, it does not display the items.
Three administration pitfalls
Averaging the eight scales
The number you get looks like a result and is not one. The eight scales do not measure the same thing and three of them mix physical and mental health: the profile goes into the notes with all eight values.
Following a patient already at 100 on a role scale
A scale at the ceiling can no longer rise. If role functioning is already maximal at baseline, the absence of progress on that line says nothing about the treatment, only about the instrument.
Using a translation found online
The publisher's permission covers its English questionnaire. A French translation circulating without a reference has neither the 1998 validation nor the responsibility that goes with it, and the measurement properties quoted here do not apply to it.
Frequently asked questions
What does SF-36 stand for?
SF-36 is short for 36-Item Short Form Health Survey. The questionnaire was published in 1992 by Ware and Sherbourne, as part of the Medical Outcomes Study.
How is the SF-36 scored?
Each item is first transformed to a 0 to 100 range, then the items of one concept are averaged. That yields eight scores out of 100, a high score signalling a better state, and no global score.
How much change counts?
The only value established by two convergent methods is around 5 points on the summary scores, measured in 310 patients operated on for a musculoskeletal tumour. It does not carry over as it stands to every population.
Is the SF-36 free to use?
Yes for its publisher's English questionnaire, which explicitly grants permission to use it with no further written permission, provided its credit line is carried and any change is identified.
Is there a validated French version?
Yes, published in 1998 by Leplège et al., preceded by a rapid translation tested in 1995. It is a distinct work from the English questionnaire, with its own conditions of use.
References
7 sources, PMIDs included
- Ware JE, Sherbourne CD. The MOS 36-item short-form health survey (SF-36). I. Conceptual framework and item selection. Med Care 1992;30(6):473-83. PMID 1593914. The original publication. Thirty-six items for eight health concepts, from limitations in physical activities to mental health, self-administered from age 14 or by interview, telephone included.
- McHorney CA, Ware JE, Raczek AE. The MOS 36-Item Short-Form Health Survey (SF-36). II. Psychometric and clinical tests of validity in measuring physical and mental health constructs. Med Care 1993;31(3):247-63. PMID 8450681. The study that sorts the scales out. Physical functioning and role-physical best distinguish degrees of medical severity; mental health and role-emotional best distinguish psychiatric disorders. Social functioning, vitality and general health measure both at once and are the hardest to interpret.
- McHorney CA, Ware JE, Lu JF, Sherbourne CD. The MOS 36-item Short-Form Health Survey (SF-36). III. Tests of data quality, scaling assumptions, and reliability across diverse patient groups. Med Care 1994;32(1):40-66. PMID 8277801. 3,445 patients, replicated across 24 subgroups. Reliability from 0.65 to 0.94, median 0.85. Floor effects negligible except for the two role scales, and above all noteworthy ceiling effects on both role scales and on social functioning.
- Perneger TV, Leplège A, Etter JF, Rougemont A. Validation of a French-language version of the MOS 36-Item Short Form Health Survey (SF-36) in young healthy adults. J Clin Epidemiol 1995;48(8):1051-60. PMID 7775992. A first, rapid French translation, tested in 1,007 Geneva residents aged 18 to 44. Internal consistency from 0.76 to 0.92 and two principal components, physical and mental. The authors explicitly present it as a stopgap before the official adaptation.
- Leplège A, Ecosse E, Verdier A, Perneger TV. The French SF-36 Health Survey: translation, cultural adaptation and preliminary psychometric evaluation. J Clin Epidemiol 1998;51(11):1013-23. PMID 9817119. The official French adaptation, by forward and backward translation with conceptual equivalence given priority. The distance between response choices was checked on visual analogue scales in 30 subjects, and face validity tested in lay panels.
- Ogura K, Yakoub MA, Christ AB, Fujiwara T, Nikolic Z, Boland PJ, Healey JH. What Are the Minimum Clinically Important Differences in SF-36 Scores in Patients with Orthopaedic Oncologic Conditions? Clin Orthop Relat Res 2020;478(9):2148-58. PMID 32568896. 310 patients operated on for a musculoskeletal tumour, with two convergent calculation methods. The minimum clinically important difference settles around 5 points for both summary scores, physical and mental.
- van Rotterdam FJ, Hensley M, Hazelton M. Measuring Change in Health Status Over Time (Responsiveness): A Meta-analysis of the SF-36 in Cardiac and Pulmonary Rehabilitation. Arch Rehabil Res Clin Transl 2021;3(2):100127. PMID 34179763. A meta-analysis of the responsiveness of the SF-36 in cardiac and pulmonary rehabilitation. The role scales explain only 24 to 27 % of the variance there, and the authors conclude that the SF-36 is not suited as a pre- to post-programme measure in those two fields.
Page written by Anthony Baillon, physiotherapist, co-founder of Physio Learning. The questionnaire itself was developed at RAND Corporation as part of the Medical Outcomes Study, and published in 1992 by Ware and Sherbourne.