What is the best design for an intervention study? Describe a hypothetical intervention study and outline
how you would design such a study. Make sure that you describe all of the essential features of the
design that you choose, and make sure that you point out why each of those features is necessary for
Intervention studies are attributed to the fact that the subjects selected for the analysis are
allocated by the investigator randomly. The study population is divided into two groups the
intervention and the control group to facilitate the achievement of the research object. The study
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is conducted mostly in epidemiological research with the aim of providing authentic findings to
the researcher (Thiese, 2014).
There are two broad types of intervention studies, which are clinical or therapeutic trials, which
are done on individuals who already have an illness with the end goal being to reduce its
recurrence or mortality of the subject. The second one is the preventative or field trial that is
conducted among individuals who are from the diseases with the aim of determining ways of
reducing the probability of the disease occurring in the test subject (Wang, 2015). The field trial
is often larger than the clinical trials as the individuals are healthy and have a longer life span
hence reducing the risks of death that may interfere with the findings of the research.
The best study design in the intervention study is the randomized controlled trial (RCT). The
design is pertinent in establishing the existence of a causal relationship between the intervention
and outcome variables (Health Knowledge, 2017).
According to Nishimura et al., (2013), participants in this analysis are divided into two groups
which are the comparison and the experimental group. The division into the two groups is done
randomly to avoid biases from affecting the findings of the research (p.28). The methods applied
in the division are; simple, block, stratified and minimized randomization. The trial group is
given the intervention being studied while the comparison group is provided with the
conventional placebo. The researcher then evaluates the reaction of the two groups to the placebo
and the intervention treatment (Charan and Biswas, 2013, p.121).
An intervention study was to be conducted to determine the low-fat diet will reduce the
occurrence of cancer. The research was conducted on women in colleges within the New York
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City in the USA who were aged between 20 to 24 years of age. The age bracket was selected
because the demographics consume significant amounts of fast foods on a daily basis, which are
having high-fat levels. 1100 students volunteered to take part in the research study, but only 920
were selected who meet the requirement of the intervention study. The requirement was that they
were not supposed to have any history of cancer in their generation tree.
The group was divided into two groups each with 460 members. One group, intervention group,
was subjected to a strict low-fat diet that composed of main vegetables, fruits, and other healthy
dishes. The other group, experimental group, was allowed to continue with their normal lifestyle
of eating fast food three times a day. The research was carried out for seven years. The members
were later on recalled and evaluated based on the analysis. The intervention group due to the
lifestyle that they were subjected to was healthy and rarely visited the hospitals. On the other
hand, the second group had some lifestyle diseases and when the research was conducted a
number had colon cancer.
In conclusion, the research design plays a significant role in the interventions studies by
introducing the authenticity of the statistical test conducted on the selected population using the
probability theory. Also, it does reduce the existence of any bias in the study, which does
enhance the validity of the findings and encourage their application in the creation of the
treatment for various illnesses. The only disadvantage of the approach is that it does not provide
an assurance of comparability as confounding differences at times occur by chance affecting the
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Charan, J., & Biswas, T.(2013). How to calculate sample size for different study designs in the
medical research? Indian journal of psychological medicine, 35(2), 121.
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Health Knowledge. (2017). Introduction to study designs- intervention studies and randomized
controlled trials. Health Knowledge
Nishimura, A., Carey, J., Erwin, P. J., Tilburt, J. C., Murad, M.H., & McCormick, J. B. (2013).
Improving understanding of the research informed consent process: a systematic review
of 54 interventions tested in randomized control trials. BMC medical ethics, 14(1), 28.
Thiese, M.S. (2014). Observational and interventional study design types; an overview.
Biochemia medica: Biochemia medica, 24(2), 199-210.
Wang, K. T. (2015). Research design in counseling. Nelson Education.