title: Efficiency of static and computer adaptive short forms compared to full-length measures of depressive symptoms.
abstract: OBJECTIVE
  Short-form patient-reported outcome measures are popular because they minimize patient burden. We assessed the efficiency of static short forms and computer adaptive testing (CAT) using data from the Patient-Reported Outcomes Measurement Information System (PROMIS) project.
  
  
  METHODS
  We evaluated the 28-item PROMIS depressive symptoms bank. We used post hoc simulations based on the PROMIS calibration sample to compare several short-form selection strategies and the PROMIS CAT to the total item bank score.
  
  
  RESULTS
  Compared with full-bank scores, all short forms and CAT produced highly correlated scores, but CAT outperformed each static short form in almost all criteria. However, short-form selection strategies performed only marginally worse than CAT. The performance gap observed in static forms was reduced by using a two-stage branching test format.
  
  
  CONCLUSIONS
  Using several polytomous items in a calibrated unidimensional bank to measure depressive symptoms yielded a CAT that provided marginally superior efficiency compared to static short forms. The efficiency of a two-stage semi-adaptive testing strategy was so close to CAT that it warrants further consideration and study.
authors: Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA. s-choi@northwestern.edu
authors: Seung W
authors: SW
authors: Choi
authors: Steven P
authors: SP
authors: Reise
authors: Paul A
authors: PA
authors: Pilkonis
authors: Ron D
authors: RD
authors: Hays
authors: David
authors: D
authors: Cella
mesh_terms: D002138:Calibration; D003198:Computer Simulation; D003863:Depression / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004185:Disability Evaluation; D006801:Humans; D008960:Models, Psychological; D011237:Predictive Value of Tests; D011594:Psychometrics / Q000379:methods; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires