Beanplot: A Boxplot Alternative for Visual Comparison of Distributions

Abstract

Boxplots and variants thereof are frequently used to compare univariate data. Boxplots have the disadvantage that they are not easy to explain to non-mathematicians, and that some information is not visible. A beanplot is an alternative to the boxplot for visual comparison of univariate data between groups. In a beanplot, the individual observations are shown as small lines in a one-dimensional scatter plot. Next to that, the estimated density of the distributions is visible and the average is shown. It is easy to compare different groups of data in a beanplot and to see if a group contains enough observations to make the group interesting from a statistical point of view. Anomalies in the data, such as bimodal distributions and duplicate measurements, are easily spotted in a beanplot. For groups with two subgroups (e.g., male and female), there is a special asymmetric beanplot. For easy usage, an implementation was made in R.