Cognitively Guided Instruction (CGI) is a professional development program that increases teachers' understanding of the knowledge that students bring to the math learning process and how they connect that knowledge with formal concepts and operations. Developed by education researchers Thomas Carpenter, Elizabeth Fennema, Penelope Peterson, Megan Loef Franke, and Linda Levi, CGI is guided by two major theses. The first is that children bring an intuitive knowledge of mathematics to school with them and that this knowledge should serve as the basis for developing formal mathematics instruction in primary school. This thesis leads to an emphasis on assessing the processes that students use to solve problems. The second thesis is that math instruction should be based on the relationship between computational skills and problem solving, which leads to an emphasis on problem solving in the classroom instead of the repetition of number facts (e.g., practicing the rules of addition and subtraction).

Evaluations demonstrated significantly superior mathematics achievement for CGI students when compared with control students on several outcomes.