The PedsQL Measurement Model is a modular approach to measuring health-related quality of life (HRQOL) in children and adolescents. The PedsQL consists of brief, practical, generic core scales suitable for use with healthy school and community populations, as well as with pediatric populations with acute and chronic health conditions. PedsQL condition-specific modules complement the generic core scales for use in designated clinical populations.

Pediatric HRQOL measurement instruments must be sensitive to cognitive development and must include both child self-report and parent proxy-report. Accordingly, the PedsQL Measurement Model consists of developmentally appropriate forms for children ages 2-4, 5-7, 8-12, and 13-18 years. Pediatric self-report is measured in children and adolescents ages 5-18 years, and parent proxy-report of child HRQOL is measured for children and adolescents ages 2-18 years.

Pediatric HRQOL instruments must have a clear conceptualization of the HRQOL construct for pediatric populations. A pediatric HRQOL instrument must be multidimensional, consisting at a minimum of the physical, mental, and social health generic core dimensions delineated by the World Health Organization (WHO) in 1948. The 23-item PedsQL Generic Core Scales were designed to measure these core dimensions of health as delineated by the WHO, as well as role (school) functioning. Thus, the multidimensional PedsQL Generic Core Scales encompass the essential core domains for pediatric HRQOL measurement: 1) Physical Functioning (8 items), 2) Emotional Functioning (5 items), 3) Social Functioning (5 items), and 4) School Functioning (5 items).

While debate continues as to the relative merits of a generic versus a disease-specific approach to measuring HRQOL, recent conceptual models indicate the advantages of an integrated modular approach to HRQOL measurement. The PedsQL Measurement Model integrates seamlessly both generic core scales and disease-specific modules into one measurement system. The PedsQL Generic Core Scales are designed to enable comparisons across patient and healthy populations. The complementary PedsQL chronic health conditions modules are designed to provide greater measurement sensitivity for circumscribed clinical populations. PedsQL Disease-Specific Modules are available for asthma, arthritis, cancer, cardiac disease, and diabetes, with additional modules in the planning stages. Thus, the PedsQL Measurement Model combines the clinical utility and sensitivity of a disease-specific measure and the applicability of generic core scales across patient and healthy populations, with healthy population norms for benchmarking purposes and community health comparisons.

The PedsQL builds on and expands a programmatic instrument development effort by Varni and his associates during the past 15 years in pediatric populations. The PedsQL 1.0, originally derived from a pediatric cancer database, was designed as a generic quality of life inventory to be utilized noncategorically, i.e., across multiple pediatric populations. Given that instrument development is an iterative process, the PedsQL 2.0 and 3.0 were further advancements in the measurement model, including additional constructs and items, a more sensitive scaling range, and a broader age range for patient self-report and parent proxy-report. The PedsQL has resulted from our rapid cycle improvement strategy, and has been field tested with children and adolescents in pediatrician's offices, hospital specialty clinics, and community settings. The PedsQL Generic Core Scales are currently in use in several school districts nationwide, as well as by State Departments of Health as a way of monitoring the health of large populations of healthy and ill children. Clinical trials and treatment interventions utilizing the PedsQL are in the planning stages internationally. The PedsQL has been translated into numerous international languages.

The PedsQL Generic Core Scales represent a substantive advancement in the PedsQL Measurement Model, with the initial field trial demonstrating excellent measurement properties in a physically healthy pediatric population. The field trial was undertaken to assess the reliability, validity, responsiveness, and practicality of the PedsQL Generic Core Scales in both physically healthy pediatric populations and in pediatric acute and chronic health conditions. A large sample of children and adolescents and their parents were administered the 23 items of PedsQL Generic Core Scales, which are printed on one side of one sheet of paper, with the instructions on the other side. Each PedsQL age-appropriate form takes less than four minutes to complete. This sample included self-reports for children and adolescents aged 5 to 18 years and proxy-report from parents of children aged 2 to 18 years.

Internal consistency reliability of the PedsQL was excellent, with alphas for the generic core scales in both self- and proxy-report greater than the 0.70 standard, and alphas for the full 23-item scale approaching 0.90 for self- and proxy-report. Missing data were minimal. Item response distributions were across the full scale range, with no floor effects, and minimal ceiling effects.

The validity of the PedsQL Generic Core Scales was demonstrated through known groups comparisons, and correlations with other measures of disease burden. The PedsQL self- and proxy-report distinguished between children with and without a chronic health condition, and within the group of children with a chronic condition, between those who did or did not have an overnight hospital visit in the last 12 months. Further, both child self-report and parent proxy-report correlated significantly with the number of days the child was too ill to pursue normal activities, needed someone to care for him or her, missed school in the last month, the number of days the parent missed from work in the last month, and parent-report of problems pursuing their normal work routine and concentrating at work. The PedsQL Generic Core Scales are also responsive to clinical change, as demonstrated in field trials.

The PedsQL Measurement Model represents a significant advancement in pediatric HRQOL measurement, combining the reliability, validity, responsiveness, and practicality not typically found all in one pediatric HRQOL instrument. Researchers, policy-makers, providers, and health plans will find the PedsQL a welcomed addition to pediatric health outcomes evaluation.

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Copyright © 1998- James W. Varni, Ph.D. All rights reserved.