Researchers use several different approaches when gathering primary data in quantitative research studies. Two of the most commonly used methods are (1) collecting data by observing participants and counting their overt acts of behavior and (2) asking people to answer fixed-response or open-ended questions. The first method is known as an observation study; the second is survey research design. The survey method uses lists of questions collected together in questionnaires—also called survey instruments—and are the most popular way to gather primary data. Because they are used so often and in all types of quantitative research designs, this chapter includes a detailed discussion on how to develop a survey research project.