The research design constitutes the blueprint for the collection, measurement, and analysis of data. It aids the scientist in the allocation of his limited resources by posing crucial choices: Is the blueprint to include experiments, interviews, observation, the analysis of records, simulation, or some combination of these? Are the methods of data collection and the research situation to be highly structured? Is an intensive study of a small sample more effective than a less intensive study of large sample? Should the analysis be primarily quantitative or qualitative?
Research design is the plan and structure of investigation so conceived as to obtain answers to research questions. The plan is the overall scheme or program of the research. It includes an outline of what the investigator will do from writing hypotheses and their operational implications to the final analysis of data. A structure is the framework, organization, or configuration of the relations among variables of a study. A research design express both the structure of the research problem and the plan of investigation used to obtain empirical evidence on relations of the problem.
These definitions differ in detail, but together they give the essentials of research design. First, the design is a plan for selecting the sources and types of information used to answer the research question. Second, it is a framework for specifying the relationships among the study’s variables. Third, it is a blueprint that outlines each procedure from the hypotheses to the analysis of data. The design provides answers for such questions as: What technique will be used to gather data? What kind of sampling will be used? How will time and cost constrains be dealt with?