MACS Manual Ability Classification SystemAIM To review classification systems for the upper limb in children with cerebral palsy (CP), and evaluate their validity, reliability, and clinical utility to make recommendations for clinical practice and future research.METHOD We comprehensively searched electronic databases to identify upper limb classification tools and associated evidence of psychometric testing. Two independent reviewers assessed the quality of the psychometric studies, and rated the clinical utility of each system using previously published tools.RESULTS Eighteen classification systems were eligible for inclusion, with two primary functions:classification of function or deformity. Published evidence of psychometric testing was available for fewer than half of the identified systems. Reliability studies were frequently limited by sample size, rater blinding, representativeness, and the number of observers. The Manual Ability Classification System (MACS) demonstrated content validity and interrater reliability. The original and modified House functional, House thumb, swan-neck, and Zancolli systems had evidence of reliability; the modified House functional system also demonstrated criterion-related validity.INTERPRETATION This review supports the use of the MACS and modified House functional system to classify upper limb function in children with CP. Similarly, the House thumb and Zancolli systems are recommended to classify thumb, and hand and wrist deformity respectively.