Changes in the law related to, and the administration of, compensation under the Motor Vehicle Insurance Act of 1972 are likely in the near future. This Act makes the treating medical practitioner an obligatory assessor of damage incurred by individuals entitled to compensation under this legislation by completion of an MVA 13 form. The value judgment of a treating practitioner and an independent medical assessor in defining injuries and disabilities subject to legal claims are discussed and 5 cases are used to illustrate the disadvantages of the treating medical practitioner as the definitive source of assessment opinion--these are lack of objectivity, perpetuation of errors of omission and lack of specialized knowledge. The very limited value (if any) of the MVA 13 form is emphasized.