The research design is a work-plan as well as structured assurance that data collected will be able to meet the purpose of the study. An empirical study is likely to use an experiment as the research design, whereas a theoretical study could use a review of archival documents or ethnography in order to understand subjective meaning. The selected method of data collection is part of the research design. Theoretical studies are generally qualitative rather than quantitative. They seek to understand why someone answers an interview question a particular way rather than how many people state a particular answer.