Part of a volume which explores current issues in service delivery to infants and toddlers (ages birth to 3) with handicapping conditions, this chapter presents program evaluation as a comprehensive process comprising three phases: input, process, and output. Three program evaluation models are summarized: Tyler's objective model, Scriven's goal-free model, and Stufflebeam's decision-making model. The latter is seen as the basis of the triphase evaluation process. Steps in the input evaluation phase are described in detail: (1) determine key elements; (2) identify sources of information; (3) develop a management plan; (4) collect data; (5) analyze and interpret data; and (6) develop an intervention program. The purpose of the second phase, process evaluation, is to monitor progress toward goals and objectives and to modify plans as needed. Research design considerations are explored in a discussion of the outcome phase, emphasizing the importance of a well-conceived, systematically implemented evaluation in order to determine the impact of the program on children, their families, and the community. Finally, standards for a high quality evaluation plan developed by the Joint Committee on Standards for Educational Evaluation are described, focusing on the four elements of utility, feasibility, propriety, and accuracy. References are appended. (JW)