The present study used a sequential mixed method design to compare special education and general education elementary teachers' self-efficacy for data-driven decision making. Participants were 127 teachers from several school divisions in a mid-Atlantic state in the United States. Dunn et al.'s (2013a) "The Data-Driven Decision Making Efficacy and Anxiety Inventory" (3D-MEA) was used for this study along with Tschannen-Moran and Hoy's (2001) "The Teachers' Sense of Efficacy Scale" (TSES), specifically the subscale on the efficacy of instructional strategies. According to the quantitative findings, there was a statistically significant difference between special education and general education teachers' "efficacy for application of data to instruction scale." The study did not reveal any statistically significant difference between special education and general education elementary teachers' beliefs about self-efficacy for DDDM in the five other factors examined in the survey. The structured qualitative interview revealed that special education and general education elementary teachers had experience with student data in pre-service classes or on-the-job training. Further, the interviews revealed that the teachers exhibited self-efficacy for DDDM in their area of certification. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]