To assist field workers in program evaluation and to explicitly discuss program strengths and weaknesses, a practical method to estimate the effectiveness of public health interventions within the existing program capacity was developed. The method and materials were tested in seven countries (Afghanistan, Zimbabwe, Tanzania, Uganda, Guatemala, the Philippines, and Ghana). In this method, four core components are assessed using a questionnaire: (1) the efficacy of the intervention; (2) the level of existing human resources (i.e., quality of recruitment, training, and continuing education); (3) the infrastructure (i.e., supplies, salary, transportation, and supervision); and (4) the level of community support (i.e., access and demand). Using the assessment tool provided, program staff can determine if all necessary elements are in place for a successful program that can deliver the specific intervention. Based on the results of the assessment program, weaknesses can be identified, explicitly discussed, and addressed.The usefulness of this tool in humanitarian relief may be twofold: (1) to assess the design and implementation of effective programs; and (2) to highlight the inevitable need for capacity building as the disaster situation evolves.