Systematic research on physics teacher education (PTE) programs in the United States is rare, owing both to the great variety of practices and structures enacted by U.S. PTE programs and to the lack of measurement tools available to measure what successful PTE programs do. To help meet the need for a specific, objective, and reliable guide for research on PTE programs, the Physics Teacher Education Coalition developed the Physics Teacher Education Program Analysis (PTEPA) rubric, which characterizes the practices and structures observed at "thriving" PTE programs (defined as programs in the U.S. that frequently graduate five or more physics teachers per year). Initial research based on the PTEPA rubric suggests that thriving programs are strong in multiple areas (especially institutional commitment, leadership, and collaboration among partners in education and physics), and that several areas of strength align with those indicated by the existing PTE literature. However, thriving programs are not necessarily strong in all areas, instead reflecting local conditions at the institutional and state level. Such findings illustrate the opportunity for measurement and hypothesis testing about the most important features that PTE programs should have.