Abstract :
The study type may dictate certain research designs. More commonly, the study objectives can be achieved through a number of alternative designs. The investigators have to select the most appropriate and most feasible design. Generally, there are two main categories of research design: observational study, and experimental or intervention study. In the observational study, the investigators stand apart from events taking place in the study. They simply observe and record. In the experimental or intervention study, the investigators introduce an intervention and observe the events which take place in the study.