In the United States, science education has experienced substantial shifts in the last decade. For in-service teachers, professional development programs (PDPs) play an important role in reform success. Despite well-known core features of effective PDPs, research still suggests a range of results among programs that claim to use those features. An analysis of the nuances associated with these core features has emerged as an important step in bridging the gap between conceptual and actual effective PD. This article presents the validation of constructs for "responsive facilitation", which may serve as a source of these nuances. Using an adapted Delphi Method, constructs were validated by multiple expert groups. A 10-construct consensus is presented with an eleventh remaining under dispute. All constructs have connections to current literature and may support the gap noted above. Implications include a structure that may provide nuance to the core features and support more consistently effective PD.