Edwards, T. C., C. E. Huebner, F. A. Connell, and D. L. Patrick (2002) Adolescent quality of life, part I: conceptual and measurement model. J Adolesc 25:275-286.
Patrick, D. L., T. C. Edwards, and T. D. Topolski (2002) Adolescent quality of life, part II: initial validation of a new instrument. J Adolesc 25:287-300.
Primary use / Purpose:
The Youth Quality of Life Instrument - Short Form (YQOL-SF) measures generic quality of life in youth ages 11-18 years with and without chronic conditions and disabilities. The short form includes 15 perceptual items measuring the domains of sense of self, social relationships, environment, and general quality of life, developed with Rasch methodology (publication forthcoming).
Conceptual and Measurement Model
This instrument was developed by asking youth about both positive and negative aspects of QOL. The creation of the conceptual model was guided by semi-structured interviews with 33 youth (ages 11 – 18 years) from various socioeconomic, health, and disability backgrounds.
The response scale ranges from 0 = not at all to 10 = a great deal or completely. The scores are summed and then transformed to a 0 to 100 scale, with a higher score representing a higher quality of life. The Multi-Trait/Multi-Item Analysis program was used to investigate the scaling assumptions and ensure the appropriateness of the scale range for each item.
Internal consistency (Cronbach's alpha) for the YQOL perceptual domains exceeded 0.80 for all four domains and for total perceptual score (Patrick et. al., 2002).
One week test-retest data were collected from 46 adolescents without chronic conditions. The intraclass correlation coefficients for each domain and the total perceptual items found were as follows: Self (0.85), Social (0.85), Environment (0.76), General QOL (0.74), and Total Score (0.78) (Patrick et. al., 2002).
Content validity was established by having youth themselves define the content of each item. Construct validity was measured by testing the items against existing measures for adolescent quality of life.
Convergent and Discriminant (Known Groups)
Convergent validity was tested by measuring the correlation between the YQOL-R and the Munich QOL Questionnaire for Children (KINDL) (Ravens-Sieberer and Bullinger, 1998). All scales of the YQOL-R correlated significantly in the expected direction with the scales of the KINDL, and the YQOL-R total perceptual score was correlated with the KINDL total score at 0.73 indicating a significant association between the two measures of perceived QoL (Patrick et. al., 2002).
Discriminant/known groups validity was established by examining associations between the YQOL-R, the Children’s Depression Inventory (Kovacs, 1992), and the Functional Disability Inventory (FDI) (Walker and Greene, 1991). The validation sample included groups of youth diagnosed with attention-deficit/hyperactivity disorder (ADHD), depression, and mobility disabilities. The Pearson’s correlation between the total YQOL-R perceptual score and the overall FDI was -0.26 compared to 0.73 with the KINDL. The results of the t-test on the difference between these correlations showed that there is a significantly higher correlation between the YQOL-R and the KINDL than between the YQOL-R and the FDI (t226 = 6.61 p < .05). Likewise the correlation of the YQOL-R with the KINDL (r = 0.73) was significantly higher than the correlation of the YQOL-R with the CDI (r = -0.58; t226 = 3.66, p < .05).
The instrument is designed for self-administration and requires approximately 10 minutes to complete. Reading level was assessed and meets a fourth grade reading level based on the Homan-Hewitt readability formula, which is intended for assessment of single-sentence constructions (Patrick et. al., 2002).