Recent efforts to better understand the process of implementation have been hampered by a lack of tools available to define and measure implementation progress. The Stages of Implementation Completion (SIC) was developed as part of an implementation trial of MTFC in 53 sites, and identifies the duration of time spent on implementation activities and the proportion of activities completed. This article examines the ability of the first three stages of the SIC (Engagement, Consideration of Feasibility, Readiness Planning) to predict successful program start-up. Results suggest that completing SIC stages completely, yet relatively quickly, predicts the likelihood of successful implementation.