This report describes the factors associated with participation in PD and highlights the individual-, program-, and system-level factors that may act as barriers to participating in specific PD activities (i.e., workshops, coaching, and college courses). We present findings from a scan of recent PD literature and share new multivariate findings from the 2012 National Survey of Early Care and Education (National Survey of Early Care and Education Project Team, 2012) that explore how often and under what conditions center-based and home-based ECE teachers and caregivers participate in PD activities. (author abstract)