Measuring health-related quality of life in adolescents: agreement betweenraters and between methods of administration

The aim of this study was to evaluate the agreement between children and pr oxies as well as the agreement between methods of administration in assessi ng Health-Related Quality of Life (HRQoL) using the TNO AZL Children's Qual ity Of Life (TACQOL) questionnaire. A random sample from a Dutch cohort of 14-year-old very low birth weight children and their parents were invited t o participate in a face-to-face (n = 150) or telephone interview (n = 150). Participants were also sent a questionnaire by mail. The response rate was 83%. Inter-rater and intermethod agreement were generally good in observab le HRQol domains, and moderate in less readily observable, and possibly les s stable, domains such as moods, pain and physical symptoms, and social fun ctioning. In measuring children's HRQoL using the TACQOL, the results and t heir interpretation are dependent on the source of information and the meth od of administration.