ABSTRACT
Deciding what data to collect entails decisions about what type of information is needed and the method by which it should be collected. This chapter presents a relevant terminology used in research design, methods of identifying data elements necessary for a research project, and methods for choosing the best data elements in the presence of several options. It covers the concepts of metadata pertaining to data elements and other attributes necessary to completely specify a data element. The chapter discusses the natural tension between limited resources and complete data definition as the difference between data collected for a single use and data that will be reused over time, and by individuals not involved in their initial definition and collection. It aids the reader to identify the data elements necessary for a research study, and to choose and apply an appropriate level of data definition and documentation for his or her research.
