Comprehensive evaluations, the type of evaluation, involve analyzing needs assessment data, process evaluation data, effect evaluation data, and cost evaluation data as a set of data. Given the resources needed to integrate analysis of various types of data to draw conclusions about the effectiveness and efficiency of the program, comprehensive evaluations are relatively uncommon. A sixth type of evaluation is a meta-evaluation. A meta-evaluation is done by combining the findings from previous outcome evaluations of various programs for the same health problem. The purpose of a meta-evaluation is to gain insights into which of the various programmatic approaches has had the most effect and to determine the maximum effect that a particular programmatic approach has had on the health problem. This type of evaluation relies on the availability of existing information about evaluations and on the use of a specific set of methodological and statistical procedures. For these reasons, meta-evaluations are less likely to be done by program personnel; instead, they are generally carried out by evaluation researchers. Meta-evaluations that are published are extremely useful in program planning because they indicate which programmatic interventions are more likely to succeed in having an effect on the participants. Published meta-evaluations can also be valuable in influencing health policy and health funding decisions.