Development and psychometric evaluation of the PROMIS Pediatric Life Satisfaction item banks, child-report, and parent-proxy editions

To describe the psychometric evaluation and item response theory calibration of the PROMIS Pediatric Life Satisfaction item banks, child-report, and parent-proxy editions. A pool of 55 life satisfaction items was administered to 1992 children 8-17 years old and 964 parents of children 5-17 years old. Analyses included descriptive statistics, reliability, factor analysis, differential item functioning, and assessment of construct validity. Thirteen items were deleted because of poor psychometric performance. An 8-item short form was administered to a national sample of 996 children 8-17 years old, and 1294 parents of children 5-17 years old. The combined sample (2988 children and 2258 parents) was used in item response theory (IRT) calibration analyses. The final item banks were unidimensional, the items were locally independent, and the items were free from impactful differential item functioning. The 8-item and 4-item short form scales showed excellent reliability, convergent validity, and discriminant validity. Life satisfaction decreased with declining socio-economic status, presence of a special health care need, and increasing age for girls, but not boys. After IRT calibration, we found that 4- and 8-item short forms had a high degree of precision (reliability) across a wide range (> 4 SD units) of the latent variable. The PROMIS Pediatric Life Satisfaction item banks and their short forms provide efficient, precise, and valid assessments of life satisfaction in children and youth.