Psychometric analysis of the Brazilian-version Kidscreen-27 questionnaire

Background The objective of this study was to verify the reliability, discriminatory power and construct validity of the Kidscreen-27 questionnaire in Brazilian adolescents. Methods Adolescents that participated of the pilot study (210 adolescents; 52.9% boys; 13.7 years old) and of the baseline (816 participants; 52.7% girls; 13.1 years old) of the Movimente Project in 2016/2017 composed the sample of the present study. This project was carried out in six public schools in the city of Florianopolis, Santa Catarina, Brazil. Test-retest reproducibility was assessed by the intraclass correlation coefficient and Gwet coefficient; internal consistency through McDonald's Omega; Hankins' Delta G coefficient verified the scale's discriminatory power and; confirmatory factor analysis to assess construct validity. Results Reproducibility values ranged from 0.71 to 0.78 for the dimensions (ICC), and ranged from 0.60 to 0.83 for the items (Gwet). McDonald's Omega (0.82-0.91) for internal consistency measures. Discriminatory power ranging from 0.94 for the dimension Social Support and Friends to 0.98 for Psychological Well-Being. The factorial loads were > 0.40, except for item 19 (0.36). The fit quality indicators of the model were adequate (X-2[df] = 1022.89 [311], p < 0.001; RMSEA = 0.053 (0.049-0.087); CFI = 0.988; TLI = 0.987), confirming the five-factor structure originally proposed. Conclusions The Brazilian-version Kidscreen-27 achieved good levels of reproducibility, internal consistency, discriminatory power and construct validity. Its use is adequate to measure the health-related quality of life of adolescents in the Brazilian context.