RESEARCH PAPER – SCIENCE EDUCATION Beyond the professional development academy: Teachers’ retention of discipline-specific science content knowledge throughout a 3-year mathematics and science partnership Renee M. Clary 1 | Anastasia Elder 2 | James Dunne 3 | Svein Saebo 4 * | Debbie Beard 4 * | Charles Wax 1 * | Deborah L. Tucker 5 1 Department of Geosciences, Mississippi State University, Mississippi State, Mississippi 2 Department of Counseling, Educational Psychology, and Foundations, Mississippi State University, Mississippi State, Mississippi 3 Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 4 Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 5 Independent Science Education Consultant, Napa, California Correspondence Renee M. Clary, Department of Geosciences, Mississippi State University, P.O. Box 1705, Mississippi State, MS 39762. Email: RClary@geosci.msstate.edu Abstract The Teacher Academy in the Natural Sciences (TANS) provided middle school (U.S. Grades 6–8) teachers (N 5 81) with intensive professional development (PD) in chemistry, geosciences, and physics, with teachers enrolled in one scientific discipline per year. Because some teachers were retained and rotated into different disciplines, the TANS program investigated retention of science content 1–2 years beyond an instructional year. All teacher participants exhibited significant gains (p < .001), in chemistry, geosciences, or physics content, between their incoming knowledge and the 10-day summer academy’s conclusion. Chemistry and geosciences content were retained until the end of the PD year. Physics participants reported a significant loss (p < .001), although gains from teachers’ incoming knowledge were still significant. When retention was measured beyond the instructional year, only the geosciences content was retained. Chemistry and physics gains were not retained, with no signifi- cant differences between incoming teachers’ knowledge and content 1–2 years post instruction. Our research indicates that science content support is needed after PD programs, and importantly, that the support differs between scientific disciplines. KEYWORDS content regression, content retention, professional development, retention, science teacher education, teacher education-in-service teachers, teacher science content 1 | INTRODUCTION In the southern United States, in-service teacher professional development (PD) program opportunities tend to be abun- dant. Universities, teacher preparation centers, and school districts seek and procure funding to provide developmental activities for in-service teachers to increase their science con- tent knowledge, learn effective classroom techniques, and improve their teaching efficacy. In recent years, the Next Generation Science Standards (NGSS; NGSS Lead States, 2013) and Common Core State Standards Initiative (CCSSI; National Governors Association Center for Best Practices, Council of Chief State School Officers, 2010) provided fur- ther impetus to recruit science teachers for PD programs—in order to optimize classroom implementation of the new NGSS and CCSSI. Funding opportunities and PD programs can make a dif- ference in our teachers’ content knowledge, pedagogical skills, and ultimately, in student performance. However, PD programs tend to be fairly short in duration, and even longi- tudinal programs eventually come to an end. How effective are science PD programs for in-service teachers’ changes beyond the PD instruction? Our PD program, Teacher Acad- emy in the Natural Sciences (TANS), provided a convenient platform against which we could measure retention of teacher science content knowledge gains beyond a specific *Retired. School Science and Mathematics. 2018;118:75–83. wileyonlinelibrary.com/journal/ssm V C School Science and Mathematics Association | 75 Received: 23 July 2017 | Revised: 28 October 2017 | Accepted: 2 December 2017 DOI: 10.1111/ssm.12267 j