Requiring a failing student to repeat a grade is, of course, not a novel idea. The theory behind test-based promotion policies is that students who fail to demonstrate a sufficient understanding of their current grade's curriculum lack the prerequisite proficiency to fully engage in the following grade. This view recognizes the cumulative nature of the curriculum across grades. However, very little causal evidence exists on whether grade retention generates negative behavioral outcomes. This study examines the impact of grade retention under a comprehensive student promotion policy instituted by the New York City Department of Education (NYCDOE). Building off earlier work that examined impacts on test scores, the current study aims to examine effects on various measures of behavioral outcomes using a quasi-experimental regression discontinuity research design. Data analyses are ongoing and the authors could not draw firm conclusions by the time of the SREE conference in March 2015, however, they expect to have solid results at a future date that will shed light on whether or not grade retention leads to the behavioral problems that critics of the policy contend that it does. Tables and figures are appended.