Focusing on the Community Action Program, an assessment was made of how much change has occurred in institutions which deal with the poor; what role CAP has played in realizing these changes, which CAP aspects or activities were related to institutional change; and community characteristics which might explain the changes or the role of CAP. Leaders of the poor and other community leaders were interviewed, along with employers and agency administrators, in 100 cities of over 50,000 population. Institutional change processes appeared to be largely political, involving cooperative behavior (as opposed to mere delivery of services) through alliances between important community groups. Help from personnel of neighborhood centers contributed to cooperation and had an independent effect on change in urban schools, employers, and private welfare agencies. Local militancy was related to changes in the operation of organizations which serve or may help the poor. However, in very large cities with sizable black communities, many alliances, and a high level of militancy, aid to community organizations was unrelated to CAP impact. Local CAP organization efforts had significantly more impact on urban schools than on employment policies or social service agencies. (LY)