The evaluation research approach contains the potential for providing reliable cause and effect statements regarding the impact of social action programs. Although there have been calls for the use of evaluation research in the coastal zone field, it appears that there have been few, if any, such studies that have actually been conducted. We provide an illustration of the use of the evaluation research methodology in the coastal zone context by presenting a study of the impact of the California Coastal Zone Conservation Act of 1972 on beach use in the Malibu area in southern California.