This paper describes the development and reliability testing of the Gross Motor Function Classification System (GMFCS) for children with cerebral palsy — a five-level ordinal scale built through a four-phase process: literature review and data examination, nominal group consensus, international Delphi survey, and interrater reliability testing across five centres.
Before the GMFCS, no validated system existed to classify motor severity in cerebral palsy — clinicians used terms like 'mild,' 'moderate,' and 'severe' that varied by observer, making cross-study comparison impossible.
This paper gave the field a reproducible common language grounded in functional limitation rather than impairment, enabling stratification in clinical trials, surgical outcome research, and epidemiologic registries across the hundreds of operative procedures proposed for CP. It directly enabled motor growth curve development (the longitudinal Ontario cohort study the authors describe as underway), long-term stability studies including McCormick et al. (2007) on GMFCS stability into adulthood, and became the foundation for multidisciplinary treatment planning recognized across North America, Europe, and Australia.
This paper describes the development and reliability testing of the Gross Motor Function Classification System (GMFCS) for children with cerebral palsy — a five-level ordinal scale built through a four-phase process: literature review and data examination, nominal group consensus, international Delphi survey, and interrater reliability testing across five centres.
Before the GMFCS, no validated system existed to classify motor severity in cerebral palsy — clinicians used terms like 'mild,' 'moderate,' and 'severe' that varied by observer, making cross-study comparison impossible.
This paper gave the field a reproducible common language grounded in functional limitation rather than impairment, enabling stratification in clinical trials, surgical outcome research, and epidemiologic registries across the hundreds of operative procedures proposed for CP. It directly enabled motor growth curve development (the longitudinal Ontario cohort study the authors describe as underway), long-term stability studies including McCormick et al. (2007) on GMFCS stability into adulthood, and became the foundation for multidisciplinary treatment planning recognized across North America, Europe, and Australia.