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Table 3 Reliability, agreement and smallest detectable change

From: Measurement properties of PROMIS short forms for pain and function in patients receiving knee arthroplasty

 

Cronbach’s αa

ICCa

SEMagr

SDC90

Effect size based on SEMagr

PROMIS PAIN

0.84 (0.79 to 0.88)

0.93 (0.88 to 0.96)

3.55

8.28

5.51

PROMIS PI

0.90 (0.87 to 0.92)

0.90 (0.83 to 0.94)

3.34

7.78

4.84

PROMIS PF

0.88 (0.84 to 0.91)

0.97 (0.94 to 0.98)

1.72

4.02

6.33

OKS

–

–

1.78

4.15b

9.52

  1. ICC intraclass correlation coefficient; SEMagr agreement for T-scores assessed using standard error of measurement from test–retest; SDC90 smallest detectable change for individuals that can be considered above the measurement error with a 90% confidence level; Effect size based on SEM, agr calculated as absolute value of the mean change score divided by SEMagr PROMIS Patient Reported Outcomes Measurement Information System; PAIN pain intensity; PI pain interference; PF physical function; OKS Oxford Knee Score
  2. a95% confidence interval in parentheses
  3. bAccording to: Beard DJ, Harris K, Dawson J, Doll H, Murray DW, Carr AJ, et al. Meaningful changes for the Oxford hip and knee scores after joint replacement surgery. J Clin Epidemiol. 2015;68(1):73–9