Since 1995, the Buck Institute has partnered with university economists and expert teachers to create the Problem Based Economics curriculum. The curriculum was developed to respond to NCEE (National Council on Economic Education) standards, and it is supported by professional development for teachers. This study examines whether the Problem Based Economics curriculum developed by the Buck Institute for Education improves grade 12 students' content knowledge as measured by the Test of Economic Literacy, a test refined by NCEE over decades. Students' problem-solving skills in economics were also examined using a performance task assessment. In addition to the primary focus on student achievement outcomes, the study examined changes in teachers' content knowledge in economics and their pedagogical practices, as well as their satisfaction with the curriculum. From observations in intervention and control classrooms, it did not appear to the research team that having and using the problem-based learning curriculum automatically enforced a more hands-on, exploratory classroom learning style. Additional study in this area might help to refine the pedagogical strategies and allow for additional support and practice for teachers on implementing the curriculum effectively. Appendices include: (1) Study power estimates based on the final analytic samples; (2) Procedure for assigning new strata to the final analytic sample; (3) Scoring procedures for the performance task assessments; (4) Sample test/survey administration guide; (5) Teacher-level baseline equivalence tests; (6) Additional student-level baseline equivalence tests; (7) Estimation methods; (8) Summary statistics of teacher data from teacher surveys; (9) Sensitivity of impact estimates to alternative model specifications; and (10) Explanations for sample attrition. (Contains 7 figures, 35 tables, 2 boxes and 16 footnotes.)