The study question, logistical, sampling, and budget issues determine the data collection method. This chapter considers the suitability of various methods for different research questions. It addresses issues of feasibility, logistics of instrument design, and methods to enhance response rates and data quality. The design and use of data collection instruments are central activities in quantitative studies. Data collection instruments can be fully structured or semistructured. Semistructured instruments allow both quantitative and qualitative analysis. The chapter discusses three major categories of data collection, namely self-administered surveys, in-person interviews, and direct observation. The computerized self-administered questionnaire (CSAQ) or audio computer-assisted self-interviewing (audio-CASI) approach to data collection has recently been developed to facilitate the private collection of sensitive data by allowing respondents to interact with a computer rather than an interviewer. Computer-assisted telephone interviewing systems (CATI) are also available to improve the efficiency of data collection tasks.