Objective: The General Life Functioning Scale (GLF) was developed to provide a complementary alternative to existing measures of impairment. We examined the psychometric properties of the GLF-Parent version (GLF-P), given the known value of informant ratings.
Methods: The GLF-P was administered to parents of adults with attention-deficit/hyperactivity disorder (ADHD) diagnosed in childhood and a nonADHD comparison group in the Pittsburgh ADHD Longitudinal Study. GLF-P ratings described 334 participants (ADHD = 186; comparison = 148) rated at age 25 (Mage = 24.80 years, SDage = 0.46, range = 24-26) and 401 participants (ADHD = 237; comparison = 164) rated at age 30 (Mage = 29.30, SDage = 0.64, range = 28-33). Exploratory (EFA) and confirmatory (CFA) factor analyses were used.
Results: EFAs suggested and CFAs confirmed a five-factor solution. We found measurement invariance across diagnostic and age groups, satisfactory internal consistency, construct validity, and known-group validity.
Conclusion: Psychometric results suggest the GLF-P as a helpful adjunctive measure of functioning. Further research is needed to determine the utility of the GLF across diverse settings.
Keywords: attention-deficit/hyperactivity disorder (ADHD); confirmatory factor analyses (CFA); exploratory factor analyses (EFA); functional impairment; measurement invariance; psychometric evidence.
© 2021 Wiley Periodicals LLC.