The ICIDH-2 serves as a useful framework for differentiating measurement by dimensions of the disabling process. Such differentiation is important to achieve more valid measurement of health related outcomes. We have attempted to examine one intervention, treatment with botulinum toxin type A, for one patient population, children with cerebral palsy, and to describe the outcome measures used in the evaluation of that intervention using this evolving classification system. This process supports the concept that measurement of health outcomes should focus on the nature and extent of functional limitations in physical, social and psychological domains. The selection of measurement outcomes must be determined not only by the requirements of the scientific process but also by the needs of the patients who are the intended beneficiaries of the intervention.