Polling political elites, academics, or other types of knowledgeable experts has provided scholars with a trove of information about political institutions, processes, and local context. Expert surveys are an especially useful method for measuring concepts that would be difficult or impossible to measure through alternative strategies and permits scholars to create indicators that are comparable across diverse contextual settings. This chapter provides an overview of the key questions researchers face when using experts as a tool of measurement. It highlights considerations regarding survey design, questionnaire design, and aggregation procedures with an eye toward identifying ways to enhance the validity and reliability of expert-based measures. The chapter also emphasizes the importance of design transparency and systematic reporting of procedures and measures of uncertainty about scores derived from expert surveys.