Because usability data can be expensive to collect and analyze, it is important that you collect the data you need to answer the usability test-questions. The article describes a two-part strategy to help with this aspect of a usability study. The first part of the strategy is to investigate the questions the product team has about its product and turn these questions into well-defined usability questions. The second part is to take those usability questions and develop a data crosswalk, a framework that gives you a systematic way to decide what specific evidence you need to answer the test questions, and what data you need to collect to get that evidence.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>