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Table 1 Targeting, reliability and sample measurement validity

From: Psychometric performance of the PROMIS® depression item bank: a comparison of the 28- and 51-item versions using Rasch measurement theory

 PROMIS-51PROMIS-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 coverage27%15%
 Item threshold/sample coverage60%60%
 Floor/ceiling effects %3/0%7/0%
Reliability
 Person Separation Index (PSI)0.950.93
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 rangen = 139 (17%)n = 148 (19%)
 Item-trait interaction: Chi-square (p-value)1720.3 (p < 0.001)401.5 (p < 0.001)
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