Methods of planning based on systems ideas, behavioral science concepts, and heuristics were used to develop plans in a field setting, to contrast the merits of these planning approaches. Plans were evaluated by experts as well as decision makers and staff in the participating organization. Criteria such as quality, acceptance, and measures of innovation were used to contrast the plans. The perceptions of agency representatives that participated in the planning groups were also obtained. The systems method used planning groups that were composed solely of experts. In the systems method, objectives were established in the first phase of the meeting, and used as a basis to structure the development of plans. For example, the intent of the service delivery plan was established before recommendations were developed. The behavioral approach used clients, the recipients of the service to be planned, as planning groups members. These groups developed a list of priority client problems which were used as a focus to formulate plans. The heuristic approach was applied to simulate trial and error planning. In this approach, no structure was used in the generation of plan components, the leader merely recorded the ideas that were stimulated by a statement of the problem. In the heuristic approach, half the planning groups had just clients as members and the rest were made up of experts. The three methods of planning were applied to two problems—the development of plans for primary health care services, and home health care delivery mechanisms. In all, twelve distinct planning groups participated permitting a replication of each “problem-planning topic” contrast. The results of the experiment indicated that the systems approach produced better quality plans while the behavioral approach produced more new ideas. This suggests that involving an organization's client in planning of services to define their problems provides a rich array of ideas for the planning process, but that systems approaches and experts are needed to formulate these ideas and consolidate them into a viable plan. However, the participants found their experiences to be significantly less satisfactory when a systems approach was used. Several other implications of these findings for planning practice are discussed.