Psychometric Properties of the Conners’ 3 Parent Rating Scale in a Clinical Sample of Iranian Children

Background Attention-Deficit/Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder among children that significantly affects academic, social, and emotional functioning. Early diagnosis is essential, highlighting the need for reliable and valid screening tools. The Conners’ Rating Scales (CRS) are frequently used for ADHD assessment; however, the psychometric properties of the latest version, the Conners' Parent Rating Scale-3 (Conners 3-P), have not yet been examined in Iranian clinical populations. Methods This study aims to evaluate the reliability and validity of the Conners 3-P Short Form in a clinical sample of Iranian children aged 6 to 12 years. The study involved 135 children, including 55 diagnosed with ADHD and 80 typically developing children. ADHD diagnoses were confirmed using the Kiddie Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL_5). Parents completed the Conners 3-P and the ADHD Rating Scale-IV. Reliability was evaluated through Cronbach’s alpha and test-retest analysis, while validity was assessed using exploratory factor analysis (EFA), convergent validity testing, and Receiver Operating Characteristic (ROC) analysis. Results The EFA identified six factors: inattention, hyperactivity, learning problems, parents' negative attitude, aggression, and parents' positive attitude, accounting for 52.22% of the variance. The Conners 3-P demonstrated strong internal consistency (Cronbach’s alpha = 0.93) and excellent test-retest reliability (ICC = 0.86). Convergent validity analysis showed significant correlations between the Conners 3-P subscales and ADHD-RS-IV scores, particularly in hyperactivity (r = 0.638, p < 0.01). The ROC curve indicated high diagnostic accuracy (AUC = 0.92), with a cutoff score of 38.50 achieving 80% sensitivity and 89% specificity. Conclusions The Conners 3-P Short Form is a reliable and valid tool for assessing ADHD symptoms in Iranian children. Its strong psychometric properties support its clinical utility in diagnosing and monitoring ADHD. Future research should investigate its applicability in broader populations.