%0 Journal Article
%@ 1438-8871
%I JMIR Publications
%V 25
%N 
%P e45334
%T Graded Response Model Analysis and Computer Adaptive Test Simulation of the Depression Anxiety Stress Scale 21: Evaluation and Validation Study
%A Kraska,Jake
%A Bell,Karen
%A Costello,Shane
%+ School of Educational Psychology and Counselling, Faculty of Education, Monash University, 19 Ancora Imparo Way, Clayton, 3800, Australia, 61 399052896, jake.kraska@gmail.com
%K graded response model
%K DASS-21
%K CAT
%K computer adaptive testing
%K simulation
%K psychological distress
%K depression
%K anxiety
%K stress
%K simulation
%K mental health
%K screening tool
%K tool
%K reliability
%K development
%K model
%D 2023
%7 22.6.2023
%9 Original Paper
%J J Med Internet Res
%G English
%X Background: The Depression Anxiety Stress Scale 21 (DASS-21) is a mental health screening tool with conflicting studies regarding its factor structure. No studies have yet attempted to develop a computer adaptive test (CAT) version of it. Objective: This study calibrated items for, and simulated, a DASS-21 CAT using a nonclinical sample. Methods: An evaluation sample (n=580) was used to evaluate the DASS-21 scales via confirmatory factor analysis, Mokken analysis, and graded response modeling. A CAT was simulated with a validation sample (n=248) and a simulated sample (n=10,000) to confirm the generalizability of the model developed. Results: A bifactor model, also known as the “quadripartite” model (1 general factor with 3 specific factors) in the context of the DASS-21, displayed good fit. All scales displayed acceptable fit with the graded response model. Simulation of 3 unidimensional (depression, anxiety, and stress) CATs resulted in an average 17% to 48% reduction in items administered when a reliability of 0.80 was acceptable. Conclusions: This study clarifies previous conflicting findings regarding the DASS-21 factor structure and suggests that the quadripartite model for the DASS-21 items fits best. Item response theory modeling suggests that the items measure their respective constructs best between 0θ and 3θ (mild to moderate severity). 
%M 37347530
%R 10.2196/45334
%U https://www.jmir.org/2023/1/e45334
%U https://doi.org/10.2196/45334
%U http://www.ncbi.nlm.nih.gov/pubmed/37347530