Agency leaders completed a web‐based survey describing their policies, procedures, and practices. Results revealed that the only individual Standard that was predictive of match length was the Training Standard. In addition, the sum total of both Benchmark program practices and Standards were associated with match length and long‐term relationships; however, neither predicted premature match closure. Results are discussed in terms of the importance of implementation of evidence‐based practices, particularly mentor training, for achieving effective mentoring outcomes. (Publisher abstract modified)