The Jim Joseph Foundation Professional Development Initiative has taken place over the past three years on a series of registers: first, for the more than 400 educators who participated in the various program cohorts managed by 10 program providers; then, for each of the organizations who led those programs, and especially for the program directors who themselves made up a cohort of their own; and finally for the broader field of Jewish education for which this collective effort has constituted a grand, even unprecedented, experiment. The Rosov Consulting team has tried to ensure that our evaluation work gave attention to each of these different strata, while also considering their intersections. Gathering data about the participating educators and what they gained from the programs while both facilitating and assessing the Professional Learning Community made up of the program directors, we have been able to observe at different orders of magnitudethe structures (the program elements) that underpin powerful professional learning whatever the context.