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Table 3 PROMIS PF full bank and short form scoring characteristics and agreement with simulated “true” scores

From: Varying the item format improved the range of measurement in patient-reported outcome measures assessing physical function

General health groups True PF
T-scorea mean (SD)
Full bank (124 items)b Format Ae (5-item short form) Format B (5-item short form) Format C (5-item short form)
T-score mean (SD) RMSEc Percentage floor/percentage ceilingd T-score mean (SD) RMSE Percentage floor/percentage ceiling T-score mean (SD) RMSE Percentage floor/percentage ceiling T-score mean (SD) RMSE Percentage floor/percentage ceiling
Poor 35.6 (6.5) 35.7 (6.4) 0.7 0.0/0.0 36.6 (6.3) 3.0 3.9/0.2 36.4 (6.3) 2.7 1.5/0.2 36.3 (6.3) 2.7 0.5/0.0
Fair 41.9 (7.6) 41.9 (7.7) 0.8 0.0/0.0 42.5 (7.9) 2.9 1.3/3.8 42.3 (790) 2.6 0.5/4.6 42.3 (7.7) 2.5 0.2/0.7
Good 48.9 (7.8) 49.0 (7.9) 1.1 0.0/0.1 49.4 (8.0) 3.2 0.1/17.0 49.4 (8.0) 3.1 0.0/21.5 49.1 (7.9) 2.6 0.0/6.2
Very good 54.4 (7.2) 54.5 (7.3) 1.5 0.0/0.2 54.5 (6.9) 3.8 0.0/37.9 54.5 (6.8) 3.7 0.0/45.4 54.4 (7.3) 2.9 0.0/16.8
Excellent 58.8 (6.5) 58.7 (6.4) 1.9 0.0/0.7 57.8 (5.3) 4.3 0.0/59.0 57.8 (5.0) 4.4 0.0/67.1 58.4 (6.3) 3.3 0.0/32.6
Full sample 47.9 (11.0) 48.0 (11.0) 1.3 0.0/0.2 48.1 (10.4) 3.5 1.1/23.6 48.1 (10.5) 3.4 0.4/27.8 48.1 (10.5) 2.8 0.1/11.3
  1. a T-scores have a mean of 50 and standard deviation of 10 in the analytic sample. bFinal Patient Reported Outcomes Measurement Information System Physical Function (PROMIS PF) item bank version 1.0. cRSME = root mean square error between estimated T-scores and simulated “true” T-scores. dPercentage of the simulated sample who reached the lowest (“floor”) or highest (“ceiling”) possible score. eFormat A: “Are you able to …” (five-category response scale from “Without any difficulty” to “Unable to do”); Format B: “Does your health now limit you in …” (five-category response scale from “Not at all” to “Cannot do”); format C: “How difficult is it for you to…” (six-category response scale from “Very easy” to “Impossible”)