Progress-monitoring data collection is an essential skill for teachers serving children for whom the general curriculum is insufficient. As the field of early childhood education moves toward tiered service provision models, the importance of routine data collection is heightened. Therefore, we evaluated the effects of a training package on preschool teachers' implementation of progress-monitoring strategies to collect data on children in need of supports beyond those provided through the general curriculum. This study employed a single-case experimental design in which generalized teacher behavior was collected within the context of the design. In addition, masked reliability data collectors were used throughout the study and an analysis of bias was conducted by a researcher unaffiliated with the study. Social and ecological validity data were collected using a multi-method approach.