Boxplot whiskers for a journal publication using APA style guide I want to submit a manuscript with a journal recommending the APA style guide for formatting. 

When looking at my boxplots, a colleague of mine wondered why the whiskers do not represent the 95% confidence interval. So I learned that the default setting for matplotlib is 1.5 IQR, which I did not questioned until that point.

According to the very good Wikipedia article on boxplots there are different possibilities for whiskers representation:


the minimum and maximum of all of the data
the lowest datum still within 1.5 IQR of the lower quartile, and the highest datum still within 1.5 IQR of the upper quartile (often called the Tukey boxplot)
one standard deviation above and below the mean of the data
the 9th percentile and the 91st percentile
the 2nd percentile and the 98th percentile


Does anybody know what is the most common whisker boundary and if there is a recommendation in the APA style?
Major statistical software such as Stata, SPSS, SAS, and R all use John Tukey's definition (hyperlinks are to the related technical documents), with various degrees of customizability. Some of them also cite William Cleveland's scheme, which is the same as Tukey's.


  one standard deviation above and below the mean of the data


This does not make sense as box plot is largely a device to display the central tendency of data using the more robust percentile statistics and I have a hard time pairing it with standard deviations (and its related statistics standard error and 95% CI), which based on the actual value of the data rather than their rank. If showing mean and SD (or SE) is the motive, there are error bar plots for this purpose.


  the minimum and maximum of all of the data


While min and max also indicate spread, they are also sensitive to extreme values, and hence a less robust indicator of dispersion. So also not making much sense.


  the 9th percentile and the 91st percentile &amp; the 2nd percentile and
  the 98th percentile


I have less opposition against these schemes, the only reason I'd opt for not using them is just we don't need any more schemes.

So, my bet is on Tukey's. And if you're uncertain if readers may be confused, by all means in the footnote state that the scheme is based on Tukey's box plot.