Describing the status of children with cerebral palsy (CP) and quantifying change in their status are 2 central challenges to research and clinical management of CP. The science of assessing and reporting status is outcome measurement, and it is rapidly developing in the arena of CP. Because of the large number of domains to measure, the variability of CP manifestations, and a limited number of "gold standard" evaluations, creating an accurate, comprehensive, responsive, and broadly applicable measurement strategy is a serious endeavor. A range of outcome measures are available to address CP issues across the spectrum of disability. The use of these measures, and others yet to be developed, provides researchers and clinicians the best means of understanding CP and the effects of treatments.