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Effect Of Removing Outliers On Statistical Inference: Implications To Interpretation Of Experimental Data In Medical Research, Todd W. Gress, James Denvir, Joseph I. Shapiro

Joseph I Shapiro MD

Background Data editing with elimination of “outliers” is commonly performed in the biomedical sciences. The effects of this type of data editing could influence study results, and with the vast and expanding amount of research in medicine, this effect would be magnified. Methods and Results We first performed an anonymous survey of medical school faculty at institutions across the United States and found that indeed some form of outlier exclusion was performed by a large percentage of the respondents to the survey. We next performed Monte Carlo simulations of excluding high and low values from samplings from the same normal …