Is it dishonest to remove outliers and/or transform data?
Hey guys, I have actually never written a blog before so I’m a little bit clueless about all this but I’m going to give it a go and hope for the best!
So many research studies are conducted within Psychology and it is clear to see that the results play a major role in supporting a researcher’s hypothesis. The results need to be as accurate as possible to ensure that the research can be a representative sample of the general public and so that it can be used by scientists, doctors etc.
Once all the data from a study is collected then it is analysed before it is shown to the scientific community. However the results usually have some data that we call outliers. These are results that lie ‘far away’ from the rest of the data. This can be due to systematic error or simply a fault in the procedure. Outliers have also been defined as values that are “dubious in the eyes of the researcher” (Dixon, 1950). However, a small number of outliers are expected in a study and I think they are important as they can change the outcomes of our data analysis.
Some people would say that by removing outliers or transforming the findings then it is manipulating the data and so the research shows what the researcher wants them to say; therefore not a true representative study. Sometimes it is because the investigator has a hypothesis to support so they try and make the findings as close as possible to the hypothesis.
It is usually fairly common in clinical psychology research for the researcher to remove patients from the analysis but I think this decision has to be justified and explained. An outlier may not be from an experimental mistake but maybe because the individual is different from others.
To conclude, I think that it is not dishonest to remove outliers even if it transforms the data. By removing the outlier the results will be more accurate and create a more reliable set of data. However, in some case where individual differences should be taken into account, then the outlier should be included.
Hope this makes some sort of sense and please leave me a comment!