Table 1 Targeting, reliability and sample measurement validity
PROMIS-51 | PROMIS-28 | |
|---|---|---|
Targeting | ||
Range (mean): person measurements | −6.14 to 4.20 (−2.17) | − 6.00 to 6.03 (2.65) |
Range (mean): item locations | −1.58 to 1.18 (0.00) | −0.68 to 1.16 (0.00) |
Range (mean): item thresholds | −3.13 to 3.12 (0.00) | − 3.46 to 3.75 (0.00) |
Item location/sample coverage | 27% | 15% |
Item threshold/sample coverage | 60% | 60% |
Floor/ceiling effects % | 3/0% | 7/0% |
Reliability | ||
Person Separation Index (PSI) | 0.95 | 0.93 |
Sample Measurement Validity | ||
Range (mean): person fit residual | −7.49 to 5.76 (−0.32) | −6.48 to 4.99 (− 0.40) |
Measurements outside recommended range | n = 139 (17%) | n = 148 (19%) |
Item-trait interaction: Chi-square (p-value) | 1720.3 (p < 0.001) | 401.5 (p < 0.001) |