Research design is one of the key procedures that a researcher must consider when undertaking any scientific research. Research design outlines how the research intends to select the study participants, the method of data collection, analysis and presentation of research findings (Mitchell & Jolley, 2013). Whether it is experimental, observational or otherwise, there has to be clearly earmarked research design for a research process. This study will apply experimental research design to collect data from the respondent, analyze the data, and present the findings of the study.
Components of Experimental Design
A study that is experimental in its design often seeks to determine whether there are causal relationships between two or more variables. There are three core components in an experimental study. These include the pre-post test design, treatment and a control group, and random assignment of respondents (Bynner & Stribley, 2010). The pre-post test component entails the researcher collecting data from participants and determining the level of performance of the selected participants. This is done before exposing them to any intervention. Then the researcher will use some of the participants as the experimental group and the others as the control group. The treatment group is exposed to interventions to monitor changes in observations and inferences (Bynner & Stribley, 2010). The control group is left without any intervention, while the experimental group is exposed to interventions that the researcher is investigating. Vogt (2012) calls for the researcher to control the intervening variables so as to empirically establish the relationship between the independent and the dependent variables under study.
In a study that involves establishing the relationship between obesity and diabetes, the researcher has to select randomly a specific number of participants who have obesity. The control group is not given any interventions while the experimental group is given an intervention to tell whether people who had been diagnosed with obesity would test to be diabetic after some time. The control group will also be examined after some time to determine whether they would also test positive for diabetes. It is based on this that inferences can be made relating to the research question and the objective as to whether patients diagnosed with obesity are likely to be diabetic.
Justifications of Experimental Design
This research methodology will be experimental in nature. This is because of the principles that experimental designs are associated with, which will be evident in this research study. One of the great features of the experimental research design evident in this study is the use of random assignment of subjects to a treatment intervention and control interventions. Mitchell & Jolley (2013) assert that the use of random intervention gives all the subjects in the study equal chances of being selected. In the case of a study aiming at determining the relationship between obesity and diabetes, the researcher will randomly select participants with obesity and test the possibility of such conditions making the participants vulnerable to diabetes. The causal relationship between obesity and diabetes is thus established by randomly exposing subjects with obesity to diabetic tests. This study is thus experimental and not observational.
Reasons for using Experimental Designs over other Research Designs
Vogt (2012) states that the advantage of experimental design over other research designs is explained by its strengths over other designs. The experimental design is more able to address internal validity threats as compared to other research designs. Enhancement of greater internal validity makes the experimental design the best research methodology that researchers can use to determine whether there is a causal relationship between obesity and diabetes. This illustrates the strength of experimental design over other research designs. Besides, the use of experimental designs enhances the chances of achieving external validity, since the findings of the study can always be generalized to the population from which the sample was drawn (Vogt, 2012).
Bynner & Stribley (2010) explain that through the control of study biases such as those associated with non-random selection of participants, experimental designs are more reliable in determining the effect of an intervention on the subjects. Besides, the use of experimental design in research methodology enables the researcher to replicate the findings of the study and the design more than once by means of using the subjects other than those used in the original study.
Experimental design methodology calls every researcher using this design to be alert, since the design is quite artificial in its approach (Vogt, 2012). A weakness that most researchers have mentioned is the fact that research controls might not replicate in natural settings. The challenges associated with introducing laboratory controls in natural settings makes many researchers resort to quasi-experimental design. However, quasi-experimental design is limited, since it is not possible to assign subjects to interventions randomly in order to determine the relationships between the independent and the dependent variables.
Biases associated with Experimental Designs
The experimental design is associated with certain biases. To begin with, it is meant to apply random sampling design, in which participants are enlisted randomly. However, in some instances researchers rarely sample the participants randomly (Vogt, 2012). This is a threat to internal and external validity of many studies. Lack of scientific procedures in the treatment of the experimental group might also introduce biases.
In conclusion, experimental design is one of the scientific methods used for the causational analysis. It may, therefore, be used to analyze causational relationship between obesity and diabetes. Its procedures limit biases in experimental design.