Dividing by Zero: Exploring Null Results in a Mathematics Professional Development Program

Background/Context Since 2002, U.S. federal funding for educational research has favored the development and rigorous testing of interventions designed to improve student outcomes. However, recent reviews suggest that a large fraction of the programs developed and rigorously tested in the past decade have shown null results on student outcomes and, often, intermediate variables. Scholars reporting on null results often explain such results by...