This paper examines factors that contributed to critical conversations in teacher communities of inquiry (CI) as part of a statewide professional development initiative in the United States. Based on a three-year mixed method design, we use qualitative comparative analysis to investigate the influence of combinations of conditions on the depth of discussion. Results suggest that there were three conditions associated with the extent to which CI members engaged in discussions with substantive interaction and reflection: a clear purpose, coach questioning, and the connection of theory to practice. The findings contribute to the understanding of effective reform implementation in different contexts.