A 5-year prospective, quasi-experimental investigation demonstrated that grade-level teams in 9 Title 1 schools using an inquiry-focused protocol to solve instructional problems significantly increased achievement. Teachers applying the inquiry protocol shifted attribution of improved student performance to their teaching rather than external causes. This shift was achieved by focusing on an academic problem long enough to develop an instructional solution. Seeing causal connections fosters acquisition of key teaching skills and knowledge, such as identifying student needs, formulating instructional plans, and using evidence to refine instruction. These outcomes are more likely when teams are teaching similar content, led by a trained peer-facilitator, using an inquiry-focused protocol, and have stable settings in which to engage in continuous improvement.