Project EQuIPD--Engaging Quality Instruction through Professional Development--sought to establish and test for efficacy a professional development model to produce highly qualified teachers in STEM practices for all children, especially for students who are in traditionally underserved schools and districts within the State of Florida. The project did this by providing two years of intensive professional development that helped teachers use system thinking to infuse technology-based inquiry into their regular instructional practices. The project also prepared the teachers, using a train-the-trainer model, so that they could train other teachers and sustain the work moving forward. This brief provides a summary of key findings from the impact study of Project EQuIPD. If specific information on program implementation and on the impact study--including the methodology and detailed impact findings--can be found in the technical report, "Improving Teachers' Instruction: The Impact of Project EQuIPD. Final External Evaluation Report" (ED618488).