THE COLLECTIVE EFFECTS OF TEACHERS’ EDUCATIONAL BELIEFS AND MATHEMATICAL KNOWLEDGE ON STUDENTS’ MATHEMATICS ACHIEVEMENT Adem Ekmekci Rice University ekmekci@rice.edu Danya Corkin Rice University dmc7@rice.edu Anne Papakonstantinou Rice University apapa@rice.edu Research suggests that teachers’ knowledge and beliefs about teaching and learning mathematics are among the key factors for effective teaching. This study explores the extent to which K-12 mathematics teachers’ educational beliefs and mathematics knowledge for teaching (MKT) have an impact on students’ math achievement. The effects of students’ prior math achievement and teachers’ years of experience and mathematics degrees earned were also examined. Hierarchical regression analysis results indicated that prior achievement was a significant student-level predictor of mathematics achievement. Teachers’ MKT and teaching experience also had a significant effect on the relation between prior achievement and current achievement. Results may have implications for teacher professional development programs as well as education policies at both district and state level. Keywords: Mathematical Knowledge for Teaching, Teacher Beliefs, Teacher Education- Inservice/Professional Development, Teacher Knowledge Purpose of the Study A significant body of research highlights the integral role that teachers’ domain-specific knowledge for teaching and their educational beliefs about teaching have on their knowledge development, decision-making and planning, and instructional practices (e.g., Parajes, 1992; Philipp, 2007). Adding to this line of research, this report extends our findings from a larger study that examined both antecedents and outcomes of teachers’ beliefs about teaching and learning mathematics (Ekmekci, Corkin, & Papakonstantinou, 2015) by connecting teachers’ beliefs and their mathematical knowledge for teaching (MKT) to student outcomes. Specifically, the current study is guided by the following research questions: (a) to what extent does a student’s prior mathematics achievement relate to their subsequent mathematics achievement, (b) to what extent do teacher-level characteristics (e.g., experience, beliefs, and MKT) relate to students’ math achievement, and (c) to what extent do the effects of student-level factors on math achievement vary by teacher-level characteristics? Literature Review Teachers’ personal and domain-specific educational beliefs should not be overlooked in the evaluation and development of effective instruction (Stipek, Givvin, Salman, & MacGyvers, 2001). There are various types of educational beliefs that math teachers possess such as self- efficacy beliefs, locus of control beliefs, and epistemic beliefs about mathematics that influence their instructional approaches (e.g., Stipek et al., 2001). Teachers’ self-efficacy can be defined as the degree to which teachers believe they can successfully perform teaching-related tasks within a particular domain or context (Enochs, Smith, & Huinker, 2000). Teachers’ locus of control may be defined as the extent to which teachers attribute student outcomes (i.e., achievement) to themselves or other (external) factors (Hofer & Pintrich, 1997). Epistemic beliefs can be perceived as beliefs about the nature of knowledge—i.e., where it comes from, its essence, and how one comes to know (Muis, 2004). Prior studies have found a strong association between teachers’ beliefs and students’