Shortening patient-reported outcome measures through optimal test assembly: application to the Social Appearance Anxiety Scale in the Scleroderma Patient-centered Intervention Network Cohort

BMJ Open. 2019 Feb 22;9(2):e024010. doi: 10.1136/bmjopen-2018-024010.


Objectives: The Social Appearance Anxiety Scale (SAAS) is a 16-item measure that assesses social anxiety in situations where appearance is evaluated. The objective was to use optimal test assembly (OTA) methods to develop and validate a short-form SAAS based on objective and reproducible criteria.

Design: This study was a cross-sectional analysis of baseline data from adults enrolled in the Scleroderma Patient-centered Intervention Network (SPIN) Cohort.

Setting: Adults in the SPIN Cohort in the present study were enrolled at 28 centres in Canada, the USA and the UK.

Participants: The SAAS was administered to 926 adults with scleroderma.

Primary and secondary measures: The SAAS, Brief Fear of Negative Evaluation II (BFNE II), Brief Satisfaction with Appearance Scale (Brief-SWAP), Patient Health Questionnaire-8 (PHQ8) and Social Interaction Anxiety Scale-6 (SIAS-6) were collected, as well as demographic characteristics.

Results: OTA methods identified a maximally informative shortened version for each possible form length between 1 and 15 items. The final shortened version was selected based on prespecified criteria for reliability, concurrent validity and statistically equivalent convergent validity with the BFNE II scale. A five-item short version was selected (SAAS-5). The SAAS-5 had a Cronbach's α of 0.95 and had high concurrent validity with the full-length form (r=0.97). The correlation of the SAAS-5 with the BFNE II was 0.66, which was statistically equivalent to that of the full-length form. Furthermore, the correlation of the SAAS-5 with the two subscales of the Brief-SWAP, and the SIAS-6, were statistically equivalent to that of the full-length form.

Conclusions: OTA was an efficient method for shortening the full-length SAAS to create the SAAS-5.

Keywords: generalized partial credit model; optimal test assembly; patient reported outcome measure; short form; systemic sclerosis.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anxiety / diagnosis*
  • Cohort Studies
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Patient Reported Outcome Measures*
  • Physical Appearance, Body
  • Reproducibility of Results
  • Scleroderma, Systemic / psychology*
  • Young Adult