Policymakers are proposing the use of outcome measures as indicators of effective principal preparation programs. The three most common metrics recommended are: (1) graduates' effectiveness in improving student achievement test scores, (2) graduate job placement rates, and (3) principal job retention once employed. This article explores the use of these three measures as indicators of program effectiveness by reviewing existing empirical research, employing program evaluation methodology to review potential approaches, and applying program evaluation standards to the evaluation effort. We conclude that the effort to evaluate principal preparation programs using these outcome measures is far less accurate than policymakers assume.