Effects of Developing Mathematical Ideas on teacher practice in the elementary mathematics classroom

International measures of student achievement in mathematics over the past decade indicate that United States' students do not perform as well as their counterparts in other countries. Reform initiatives to address this deficit have included new curriculum, revised mathematics standards, alterations in school structures, and implementing new teaching strategies with minimal results. The missing component in these initiatives has been a focus on the classroom teacher's own knowledge of and facility with mathematics and the impact this has on developing students' understanding of math.;This study explored whether elementary teachers who participated in the professional development program Developing Mathematical Ideas (DMI) implemented research-based mathematics practices more frequently than teachers who did not receive the training. The study also reviewed student achievement in classes taught by DMI-trained teachers and those teachers not trained in DMI. Instruments included a survey, interviews with 5 teachers and the state achievement results of third, fourth, and fifth grade students.;The survey results showed no differences in the frequency of implementation of research-based practices for DMI and non-DMI-trained teachers with one exception. DMI-trained teachers reported modifying the math curriculum and evaluating students' learning gaps at a higher frequency than non-DMI-trained teachers. The interviews pointed to a possible relationship between coaching following DMI training and higher teacher confidence levels in teaching math. More coaching sessions may also improve teachers' facility with mathematics. Achievement results showed no mean difference in scale scores between third and fourth grade students taught by DMI-trained or non-DMI-trained teachers. Fifth grade students taught by non-DMI-trained teachers had significantly higher mean scale scores than those taught by DMI-trained teachers.;The findings from this study point to DMI not having a robust impact on teacher practice and having no positive impact on student achievement. Survey design, sample size, program implementation, and other school district initiatives may explain some of these findings. These findings may be limited to this study and may not generalize to another setting. The implication that follow-up coaching may enhance the results of DMI training should receive further attention.