The design of a comprehensive evaluation of subsidized rural primary care programs on a large national scale is described. Its major purpose is to derive data whose analysis will answer major policy questions about the factors influencing the outcome of the major types of such programs in different communities. This first paper also delineates a typology whichIn the 1960s, the long recognized problem of making good quality personal health services available to people in rural areas was given greatly increased attention in the United States. For many years prior to this, various measures to correct this persistent deficiency had been tried by rural people themselves, by agencies such as governments at local, state, and national levels, and by local and national foundations. Few of these efforts seemed to provide satisfactory solutions. During the 1970s, growing concern about this problem led to greatly expanded and strengthened efforts and some new approaches which included the requirement that subsidized primary care projects adopt specific programmatic goals and particular methods of organization, staffing, and operation.Toward the end of the 1970s, national economic constraints produced increasing competition for the public dollar, thus heightening an interest in comprehensive evaluation studies that might lead to policy changes for future sup-