Contents lists available at ScienceDirect Journal of Affective Disorders journal homepage: www.elsevier.com/locate/jad Research paper Measurement invariance and psychometric analysis of Kutcher Adolescent Depression Scale across gender and marital status Amin Mousavi a, ⁎ , Mahnaz Shojaee b , Mehrdad Shahidi c , Ying Cui b , Stan Kutcher d a Department of Educational Psychology and Special Education, College of Education, University of Saskatchewan, Canada b Department of Educational Psychology, Faculty of Education, University of Alberta, Canada c Department of Psychology, Islamic Azad University of Central Tehran Branch, Iran d Department of Psychiatry, Faculty of Medicine, Dalhousie University, Canada ARTICLE INFO Keywords: Item response theory Depression Measurement invariance Kutcher Adolescent Depression Scale ABSTRACT Background: The Kutcher Adolescent Depression Scale (KADS) has been studied across Canada and some other countries during the past almost 15 years. The scale is a self-report tool to diagnose and monitor clinical de- pression in adolescents. A brief review of previous studies on KADS showed the lack of evaluation of KADS fairness/equivalence in measuring depression among identified groups. Methods: To examine the psychometric properties and measurement invariance of the KADS, responses of 407 participants were analyzed using item response theory (IRT) and ordinal logistic regression (OLR). Relevant measures of effect size were utilized to interpret the results. Results: Findings of the parallel factor analysis confirmed unidimensionality of the KADS and the partial credit IRT model found to be the best fitting model for analyzing the scale. OLR analysis detected three items across gender and one item across marital status to function differentially. An assessment of effect sizes implied neg- ligible differences for practical considerations. Limitations: A note of caution is necessary with respect to interpreting results of measurement invariance across Gender. The sample analyzed in this study was predominantly female and this might have affected our findings. A similar analysis with a more balanced sample is recommended. Conclusions: This study was a significant step towards providing theoretical and practical information regarding the assessment of depression among adolescents by presenting adequate evidence regarding the psychometric properties of KADS-11. Future studies may look at different methods for assessing invariance and different groups for strengthening conclusions with respect to the KADS. 1. Introduction Depression is one of the prevalent mental disorders across Canada (Centre for Addiction and Mental Health 2011; Canadian Mental Health Association-CMHA, 2013; Kimball et al., 2018; Mood Disorders Society of Canada, 2018) and around the world (World Health Organization, 2015, 2017). This disorder, which is characterized by several symptoms such as depressed mood or irritable, loss of interest, sense of hope- lessness, lack of happiness and self-withdrawal, psychomotor retarda- tion and other symptoms (Steptoe et al., 2007; Walkiewicz et al., 2012), was predicted to be the second most common mental health disorder in Canada by 2020 (WHO, 2002 cited in CAMH, 2011). It is also estimated that 70% of mental health problems have their onset during childhood and adolescence (CAMH, 2015) and young adults are at risk for de- veloping depression and other types of mental health difficulties (CMHA, 2013; Ialomiteanu et al., 2014). Thus, most clinicians, practi- tioners and counsellors endeavor to screen and diagnose depression as early as possible by relying on reliable and valid tools for further therapeutic intervention. A recent review of most frequently used depression scales by Shojaee et al. (2016) revealed that amongst various tools, the Kutcher Adolescent Depression Scale-11 Items (KADS-11) (Brooks and Kutcher, 2001; Shahidi and Shojaee, 2014) is one of the most appropriate scales possessing several vital characteristics for assessing disorders in youth such as: 1) ease of administration; 2) adequate number of items; 3) the ability to distinguish comorbid symptoms; 4) specificity and sensitivity; 5) purpose: screening or diagnosis; 6) ability to measure change over time (treatment sensitivity); 7) internal reliability and validity; 8) de- velopmentally appropriate; and 9) self-report rather than clinician ad- ministered (Brooks et al., 2003; Gesinde and Sanu, 2014;Levine, 2013; https://doi.org/10.1016/j.jad.2019.05.010 Received 5 January 2019; Received in revised form 5 March 2019; Accepted 6 May 2019 ⁎ Corresponding author. E-mail address: amin.mousavi@usask.ca (A. Mousavi). Journal of Affective Disorders 253 (2019) 394–401 Available online 06 May 2019 0165-0327/ © 2019 Elsevier B.V. All rights reserved. T