Development and Content Validity of the Wellbeing of Life Questionnaire for Overweight Adolescents

Abstract

Aim: To develop a multidimensional Wellbeing of Life Questionnaire (WOL-Q) targeting five health-related quality of life (HRQoL) domains and evaluate its content validity and factorial structure in adolescents classified as overweight.

Materials and Methods: A methodological psychometric study following COSMIN recommendations was conducted. A 31-item instrument was developed targeting Physical Functioning, Emotional Functioning, Social Functioning, Environmental Factors, and School Functioning. Six domain experts evaluated content validity using Item-Level Content Validity Index (I-CVI) and Scale-Level Content Validity Index (S-CVI/Ave). A consecutive sample of 200 adolescents classified as overweight (Asian BMI 23.0-24.9 kg/m2; aged 13-18 years) was recruited. Item analysis (corrected item-total correlations, Cronbach's alpha) and exploratory factor analysis (EFA; principal axis factoring, varimax rotation) with parallel analysis were conducted on a calibration subsample (n=100).

Results: Content validity was excellent (S-CVI/Ave=0.955; all I-CVI>=0.80). Six items with corrected r<0.20 were excluded. Parallel analysis confirmed five-factor retention. EFA explained 56.6% of variance. Tucker's congruence confirmed factor replicability (M=0.991). Overall Cronbach alpha=0.836.

Conclusion: The 25-item WOL-Q demonstrated excellent content validity and a stable five-factor structure, representing the first HRQoL instrument for adolescents classified as overweight using Asian BMI criteria.