Different levels of program evaluation should have synergy in order to facilitate effective and systematic collection, analysis and the use of data. These levels are: needs assessment, program theory assessment, process evaluation, impact evaluation and cost-effectiveness analysis. Needs assessment focuses on defining the target population, identifying a program as per needs of the population and describing alternatives to the program. Program theory assessment seeks to establish validity of the chosen program in addressing the requirements identified during the needs assessment (Rossi et al., 2004). This step attempts to answer questions regarding the requirements associated with the identified needs and the usefulness of a program in eliminating shortcomings of the prerequisites. Furthermore, program theory assessment describes the services offered in response to the identified needs. Process evaluation analyses the execution of aspects defined through the program theory assessment. This step scrutinizes the completion of tasks, delivery of services relating to identified needs, successfulness of the program in its role of intervening for the prerequisites and effectively addressing the needs of the beneficiaries.
Impact evaluation describes the changes realized through the implementation of a program. It employs aspects of the theory of change to scrutinize the expected transformation. The impact of a program is the changes that would not have occurred without the program itself. Cost-effectiveness analysis describes the benefits derived from all the evaluation steps discussed above. First, it scrutinizes the use of the output from the needs assessment step to measure the impact of the program. Secondly, it uses the output from the process evaluation stage to determine the costs associated with all the inputs in the whole evaluation exercise (Rossi et al., 2004). Thirdly, cost-effectiveness analysis uses the output from the impact evaluation stage to quantify benefits of the whole evaluation. Lastly, this step promotes comparative cost benefits realized through the identification of alternatives in the evaluation process. Thus, all the steps in the program evaluation are interdependent with the earlier step(s) providing inputs to the subsequent step(s).