Brief report: Assessing the impact of rating scale type, types of items, and age on the measurement of school-age children's self-reported quality of life

Objective To examine the effect of age, scale, and item type on the reliability and reproducibility of children's quality-of-life (QOL) responses. Methods The TedQL (ability, social, and mood items) was administered to 266 healthy children (age range of 5-6 and 7-9 years) at two time points, comparing three rating scales ( circles, faces, and thermometer). Children were given the same (n=144) or different (n=122) scales over time. Results Reliability for total QOL and ability items was highest for circles and for social items using the faces. Faces and thermometer scales showed highest reproducibility over time. Greater agreement over time across different scales was found between circles and faces (5-6 years) and thermometer and circles (7-9 years). Conclusions For maximum internal reliability, circles are recommended for ability items and faces for social items. For maximum reproducibility over time, the thermometer is recommended for 5-6 years and faces for 7-9 years.