There is no such concept as "the ideal research method". Most study types are understood and taught in a relative vacuum without appreciating their philosophical context. However, to achieve an optimal approach is more a matter of resolving the congruence between research purpose and method. Proper location of research methods within a theoretical framework is therefore important, otherwise the resulting over-simplification will eventually lead to inappropriate use of study types. Designing any type of study encompasses the process of identification, exploration and explanation, and utilizes concepts such as manipulation, sampling, replication and time dimensions. Medical research has borrowed study types both from Epidemiology and Social Sciences and practiced as observational and experimental inquiries, and we offer in the present review a framework within which these various types may be understood.