In the United States, in 2013, 610,042 people were estimated homeless in one night. Improving the effectiveness of homeless assistance programs, particularly aligning programs' practices with their goals, is critical to serving this population. Using a theory that predicts homeless exits, this study presents an innovative, low-cost evaluation tool that can be used by a wide range of human service providers to conduct more frequent "in-house" process evaluations. The Gap Assessment of Policy and Practice (GAPP) tool streamlines process evaluations thus improving social programs. To test this tool's effectiveness, we compared the results of a traditional process evaluation and a GAPP tool evaluation of a homeless assistance program. Both evaluations revealed a consistent disparity between program activities and expressed goals. The GAPP tool is less time intensive and provides a useful road map for structuring a process evaluation for program providers, thus increasing program impact by encouraging more frequent and efficient self-assessments.