many quantitative research studies are designed to test a theory that has been developed to explain some educational phenomena . however , studies also can be designed so that data are collected first, and then a theory is derived from those data. the resulting theory is called grounded theory, because it is "grounded" in the particular set of data the researcher has collected. in this research tradition, hypothesis are the outcome of the study rather than the initiators of it. the usefulness of the theory can be tested in subsequent research. this approach to theory development is more applicable to case studies.