Alcohol use from adolescence through early adulthood: an assessment of measurement invariance by age and gender

Background and aimsStudies on alcohol use and related constructs rarely test for measurement invariance to assess the reliability and validity of measures of alcohol use across different subpopulations of interest or ages. This failure to consider measurement invariance may result in biased parameter estimates and inferences. This study aimed to test measurement invariance of alcohol use across gender and age using a US nationally representative sample to inform future longitudinal studies assessing alcohol use. DesignThe National Longitudinal Study of Adolescent to Adult Health, a school-based, nationally representative longitudinal study conducted in 1994-95, 2001-02 and 2008. SettingAll regions within the United States; participants were selected via a clustered sample design from 80 high schools that represented the national population. ParticipantsYouth and young adults aged 13-31years who had valid data on all three alcohol items within wave: 18923 from wave 1; 14315 from wave 3; and 14785 from wave 4. MeasurementsAlcohol use measurement models were constructed using past-year general drinking frequency, heavy episodic drinking frequency and average quantity when drinking. Configural (factor structure), metric (factor loadings) and scalar (item intercepts) measurement invariance models were tested by gender and for each year of age from 13 to 31 years. FindingsAll models passed the threshold for configural invariance. Comparisons between males and females demonstrated metric (and usually scalar) non-invariance for most ages beyond middle adolescence. Nearly all 1- and 2-year contrasts passed metric invariance. Scalar non-invariance was most prevalent in age comparisons between late adolescence and early adulthood, particularly for tests using 2-year age increments. ConclusionsStudies that do not account for the effects of gender and age on the measurement of alcohol use may be statistically biased.