Research design is a procedural plan, and strategies utilized by a researcher to find out causes or answers to a given problem or question (Kumar, 2011). Research design and methods are developed to find solutions to the research problems under investigation. It is good to recognize that different research methods are used to answer other types of research questions. There are multiple forms of research studies that are carried out in epidemiology. As a public health official, there are different epidemiology study designs that can be utilized in different types of research. These designs include experiments, observation, and cohorts.
An experimental design involves carrying out experiments to test a hypothesis or a research question. The researcher manipulates some aspects of a phenomenon under study before inferences are deduced from the experiment. The most common characteristics of experimental design include well organized structure that clearly described through figures, tables, and charts. Additionally, experimental designs have a carefully selected framework to facilitate treatment level and treatment combination experiments, and are usually controlled (Cormack & Gerrish, 2011). Experimental designs produce strongest evidence for epidemiological studies. However, experiments are expensive and time consuming (Jekel, 2007).
Observation design is another important research design employed in epidemiology studies. Observation design involves cross-sectional surveys of populations at certain points in time through interviews and mass screening of program (Jekel, 2007). It makes use of questionnaires and surveys to collect data on a given problem. This design is fairly quick and can be performed quickly as compared to the other designs. However, its main undoing is that it does not offer evidence between risk factors and disease in epidemiology studies (Jekel, 2007).
Cohort design is applied when a researcher determines the history of a certain aspect. Cohort design studies may be prospective or retrospective with regard to the research hypothesis that is to be tested. Cohort study clearly identifies the group of people to be studied (Mann, 2012). Prospective cohort design involves choosing a group of people that do not possess the outcome that is of interest to the investigator (Mann, 2012). Different variables are measured to identify the development of the condition. Retrospective cohort study utilizes data that have already been used for other purposes, but the methodology remains similar to prospective cohort study. The major strength of cohort designs is that they can be performed prospectively or retrospectively to obtain absolute measures of risks (Jekel, 2007). The major weakness of cohort studies is that it is time-consuming and can only study risk factors that are only measurable at the beginning (Jekel, 2007).
In epidemiology, the incidence rate can best be used to gauge association in cohort studies and observations (Schoenbach, 1999). Incidence rate is appropriate since it reveals that both retrospective and prospective studies utilize exposure to factors and risks involved. On the other hand, risk ratio is used when developing experimental design. This helps identify the risk factors observe exposure to diseases and other cohorts. It also requires the establishment of relationships between variables (Schoenbach, 1999).
The research to be used in epidemiology is highly dependent on the scope and research problem that need to be unraveled. In conclusion, it should be acknowledged that every research design has its own holistic purpose in epidemiology research. The choice of any epidemiology design needs to be selected depending on the quality of information that is required and the cost effectiveness of the design.
Cormack, D.F.S. & Gerrish, K. (2011). The research process in nursing. Chichester: Wiley-Blackwell.
Jekel, J.F. (2007). Epidemiology, biostatistics, and preventive medicine review. Philadelphia, PA: Saunders.
Kumar, R. (2011). Research methodology: A step-by-step guide for beginners. Los Angeles: Sage.
Mann, C.J. (2012). Observation research Methods, Research design II: cohort, cross sectional and case-control studies. Emerg Med J. 20(1): 54-60.
Schoenbach, J.V. (1999). Analytic study designs. Web.