The Impact Factor box plot depicts the distribution of Impact Factors for all journals in the category. The horizontal line that forms the top of the box is the 75th percentile. The horizontal line that forms the bottom is the 25th percentile. The horizontal line that intersects the box is the median Impact Factor for the category. The cross represents the mean value.
Horizontal lines above and below the box represent maximum and minimum values that are no more than 1.5 times the span of the interquartile range, which is the range of values between the 25th and the 75th percentiles. These lines are commonly referred to as "whiskers."
An open circle represents an outlier, which is a single value greater or less than the extremes indicated by the whiskers.
The category box plot, which displays on the Rank in Category page, is the same as the Impact Factor box plot. It shows the Impact Factor of the selected journal so you can view the journal's Impact Factor in the context of all Impact Factors for the journal's category as depicted by the graph.
If a journal belongs to multiple categories, multiple box plots will appear.
We thank Marie-Helene Magri and Aline Solari of the Institut National de la Recherche Agronomique (INRA, France) for proposing the use of her application of the box plot concept to the Journal Citation Reports as a method of visualizing journal performance across disciplines. For a more in-depth description of the use of this approach, please see Magri, M.-H. and Solari, A. 1996. The SCI journal citation reports: a potential tool for studying journals? Scientometrics 35: 93–117. http://dx.doi.org/10.1007/BF02018235
Information About ...