Improvements in organization, time management, and planning (OTMP) skills have downstream effects on student academic performance. Brief, practical assessment tools are needed to identify students needing OTMP intervention and monitor response to intervention. The purpose of this study was to develop and validate brief rating scales of OTMP skills, derived from the Children’s Organizational Skills Scale parent and teacher versions (COSS-P, COSS-T), for screening and progress monitoring. Three samples were used: (1) general and clinical sample (n for caregivers = 1155; n for teachers = 1139; Abikoff & Gallagher, 2009); (2) sample from the randomized controlled trial (RCT) evaluating Organizational Skills Training-Tier 2 (OST-T2; n = 185; Nissley-Tsiopinis et al., 2024); (3) sample from the RCT evaluating Homework, Organization, and Planning Skills (HOPS; n = 163; Langberg et al., 2018). Based on indices of discrimination and item effect sizes, we identified 10 items from the COSS-P/T representing multiple components of OTMP interventions, in addition to one item assessing OTMP interference with performance. Confirmatory factor analyses demonstrated strong fit to a bifactor model. Only the general factor demonstrated acceptable reliability. The total score demonstrated convergent validity with measures of school and executive functioning and was excellent in differentiating children with and without substantial, impairing OTMP deficits (Area Under Curve [AUC] = .947 for COSS-P, .982 for COSS-T). Treatment sensitivity for the screeners and three, five-item formative behavior assessment measures, computed as effect sizes (Cohen’s d) based on response to OST-T2 and HOPS, all exceeded −1.20. The brief tools developed in this study have substantial utility for screening and progress monitoring.
