Thanks, Tamar, for these very thoughtful comments. A blog post in its own right! I can see that the “what” and “how” distinction is confusing, and perhaps it’s not the most helpful one anyway. I guess the “what” questions range from broad policy through to the content of services delivery; we do a lot on the former (even though as you say we don’t always have the answers) and less on the latter. As you say, a lot of the discussion the last couple of days on “deliverology” was actually structured around a different distinction, namely between policies and programs, on the one hand, and implementation on the other. “Deliverology” as currently conceived is clearly focused firmly on implementation, which begs the question of where the ideas for policies and programs come from (isn’t that part of the science of delivery?). And because governments do the implementation and the Bank supervises, the Bank doesn't have an obvious role in “deliverology” as interpreted up to now. I like your 3-item list but do (2) and (3) point to a bigger role for the Bank in implementation and hence in “deliverology”? A.