The assessment of outcomes of medical interventions is a central concern of patients, physicians, nurses, and of individuals, groups and government agencies who pay for medical care. Outcome assessments are incomplete without measurements of functional status. Functional Status Measurement in Primary Care provides an indepth discussion of psychometric issues as applied to functional status assessment and details the practical experience of Family Physicians/General Practitioners in several countries with functional status measurements in their patient populations. International experience with the use of the Darthmouth COOP Charts is described along with their practical application in the daily practice of physicians and nurses of ambulatory patients.