Software developers continue to be one of the most expensive parts of running a tech company. Understanding how developers work, and why they make certain choices, is critical to measuring and improving their productivity. At Google, we regularly utilize mixed-methods research to understand how developers comprehend their code, how they collaborate, how they spend their time, and what points of frustration they run into along the way. In this presentation, I’ll describe some studies that we’ve run at Google, highlight the methods we frequently utilize, and show how engineering leaders then use the results to make decisions that impact developer productivity.