Psychometric properties of the PROMIS ® pediatric scales: precision, stability, and comparison of different scoring and administration options

Abstract

Objectives: The objectives of the present study are to investigate the precision of static (fixed-length) short forms versus computerized adaptive testing (CAT) administration, response pattern scoring versus summed score conversion, and test-retest reliability (stability) of the Patient-Reported Outcomes Measurement Information System (PROMIS(®)) pediatric self-report scales measuring the latent constructs of depressive symptoms, anxiety, anger, pain interference, peer relationships, fatigue, mobility, upper extremity functioning, and asthma impact with polytomous items.

Methods: Participants (N = 331) between the ages of 8 and 17 were recruited from outpatient general pediatrics and subspecialty clinics. Of the 331 participants, 137 were diagnosed with asthma. Three scores based on item response theory (IRT) were computed for each respondent: CAT response pattern expected a posteriori estimates, short-form response pattern expected a posteriori estimates, and short-form summed score expected a posteriori estimates. Scores were also compared between participants with and without asthma. To examine test-retest reliability, 54 children were selected for retesting approximately 2 weeks after the first assessment.

Results: A short CAT (maximum 12 items with a standard error of 0.4) was found, on average, to be less precise than the static short forms. The CAT appears to have limited usefulness over and above what can be accomplished with the existing static short forms (8-10 items). Stability of the scale scores over a 2-week period was generally supported.

Conclusion: The study provides further information on the psychometric properties of the PROMIS pediatric scales and extends the previous IRT analyses to include precision estimates of dynamic versus static administration, test-retest reliability, and validity of administration across groups. Both the positive and negative aspects of using CAT versus short forms are highlighted.

Figures

Figure 1

Histograms from CAT response pattern EAP scores (solid outline), short form response pattern EAP scores (outline with short dashes), and short form summed score EAP scores (outline with long dashes)

Figure 2

IRT standard errors across scores, and RMSE, for CAT response pattern EAP scores (light gray dots), short form response pattern EAP scores (black dots), and short form summed score EAP scores (gray open circles)