"Project SEED" is a supplemental mathematics program for low-achieving students in grades 3 through 8 and is intended to prepare students to be successful in high school and college math. Based on the Socratic method, instruction is delivered through a series of questions to the class. In addition to individual responses, the instructor solicits group feedback through silent hand signals, chorus responses, and quick surveys of written work. The program is intended to encourage active student learning, develop critical thinking, and strengthen articulation skills. Student learning is assessed regularly, and instructors adapt the lessons to accommodate different ability levels. The curriculum, taught by mathematics specialists, includes topics from advanced mathematics, such as advanced algebra, pre-calculus, group theory, number theory, calculus, and geometry. "Project SEED" instruction is provided in addition to regular math instruction four times a week for 14 to 16 weeks. The program also provides professional development for classroom teachers through modeling, coaching, and workshops. The What Works Clearinghouse (WWC) identified 16 studies of "Project SEED" for elementary school students that were published or released between 1988 and 2011. Eight studies are within the scope of the Elementary School Math review protocol but do not meet WWC evidence standards. Five of these studies use a quasi-experimental design in which the analytic intervention and comparison groups are not shown to be equivalent prior to the start of the intervention. In the remaining three studies, "Project SEED" was offered through learning centers that provided a number of educational interventions in addition to "Project SEED". Therefore, measures of effectiveness in these studies cannot be attributed solely to "Project SEED". Eight studies are out of the scope of the Elementary School Math review protocol because they have an ineligible study design. Six of these studies do not include primary analysis of the effectiveness of "Project SEED". One study does not use a comparison group or single-case design. One study does not use a sample of elementary school students. A glossary of terms is included. (Contains 2 endnotes and 1 additional resource.)