The present paper describes the recruitment and site selection process that has been underway since January 2011, with particular emphasis on the use of Mahalanobis distance score to determine matched pairs of sites prior to randomization to treatment and control groups. Through a systematic winnowing process, the authors found that they could reduce the number of potential matching variables from more than 100 to just 11 matching variables. By computing Mahalanobis Distance scores for each eligible school, and discussing the results as a team, they were able to identify a set of matched pairs that, when randomly assigned to their two treatment conditions, produced two sets of schools that were well matched on the relevant variables, i.e., represented a level playing field for the RCT in North Carolina. They will use the same process to match and randomly assign schools in their other two regions. They hope that other researchers engaged in similar work will find this account useful. (Contains 5 tables.)