Biasness in a research study is known to cause a distortion between the exposure and outcome. Bias in a study results from errors in design method employed, method of data collection, as well as data analysis. According to a critical review of the controversial paper published (and later retracted) by Wakefield et al., which implicated the MMR vaccine as a possible etiologic contributor to autism, the researcher supported the retraction of the published paper based on the following observations: there were some mistakes that were noted concerning the data collection method used.
The authors failed to account for some major factors that are associated with autism. At the same time, Wakefield et al. were trying to find the effect of exposure to the MMR vaccine as a possible etiologic contributor to autism. However, they failed to account for important variables that influence autism, such as maternal and paternal factors, prenatal conditions of the mother, whether the mother has ever suffered from psychiatric before the conception.
Another important factor that was not factored in was the perinatal conditions such as gestation period and birth weight. Although the study failed to prove the association between autism and MMR vaccine, the study failed to meet the threshold required to make a scientific study credible. The authors’ suggestion for the reduction of the dosage for MMR vaccine among the children by being given the vaccine in three separate doses instead of a single dose as it is administered was also rejected as it lacked concrete scientific foundation. The authors of the retracted paper were noted to be biased in the selection of the participants.
The authors limited their investigations only to those children who have had previous exposure to the MMR vaccine, as well as those children that were noted to inhibit autism symptoms. This resulted in biases in the sample selection as the researchers identified cases predicated upon previous exposure. In order to have a more informative study, the researchers could have also sampled a control case comprising of those children who were not exposed to the MMR vaccine in order to validate the study outcomes. Therefore, because of the failure of the concerned researchers to factor in all important variables, while conducting the study, the paper had to be retracted as it did not reach the minimum threshold required to authenticate the paper as a credible scientific source.