Although the cries for "evidence" are frequent in the education space, evidence can prove elusive to practitioners: Where is it? How sound is it? What does it tell us about real-life situations? This essay is the first in a series that aims to put the pieces of research together so they can be used by those charged with choosing which policies and practices to implement. The conveners of this project—Susanna Loeb, the director of Brown University’s Annenberg Institute for School Reform, and Harvard education professor Heather Hill—have received grant support from the Annenberg Institute for this series.