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I've stopped using box plots (2021)

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Re: I've stopped using box plots (2021)

#4

The author just has a bad intuition. On the first picture he says "this looks like a small quantity". No, you can't say that. All you can say is that half the data points are in the shades part. You don't know where the rest are.

I don’t think intuition is the right word. If you have never seen a box plot before, your intuition will not help parse it. (Unlike violin plots.)

Re: I've stopped using box plots (2021)

#5
post #2

What about violin plots. https://en.m.wikipedia.org/wiki/Violin_plot

I was thinking the same thing while reading, but the author does mention them at the end (together with the bee swarm plot or sina plot, which I think is the better version of a violin plot)

https://www.rhoworld.com/i-swarm-you-swarm-we-all-swarm-for-...

Re: I've stopped using box plots (2021)

#6
post #2

What about violin plots. https://en.m.wikipedia.org/wiki/Violin_plot

I use violin plots but a complication is that the shape depends upon the bandwidth hyperparameter of the kernel density estimator that is used inside. The plot can differ a lot for different bandwidth values.

Selection of the 'proper' bandwidth is a classic bias-variance tradeoff problem.

Re: I've stopped using box plots (2021)

#7
When profiling slow queries/code I often collect the elapsed time of a test where I take 5-10 runs and calculate the mean/average, standard deiviation, min, and max.

As well as using line charts on the average, I've used a box plot (with the edges of the box being the mean +/- 1 standard deviation) to get an idea of whether a given change is significant or not. I.e. if the boxes are close together I will ignore a change I've made, only committing changes that provide a significant jump in performance. The box plot is a useful way of visualizing that.

They can help with seeing highly variable performance (long box) from consistent performance (narrow box).

I can see this in the data (mean, standard deviation) but having it represented visually can help -- especially looking at the data over several iterations, or when looking for patterns from changing a variable (like the number of items in the data being processed).

I've also used linear regression calculations when data has looked linear or quadratic to check/confirm that assumption. -- You can overlay that on top of the data by computing the values for each value of n along side the actual data average and then including the average and calculated values in a line chart.

Re: I've stopped using box plots (2021)

#8
So the diagram should not be used because of an education problem with some audiences?

Isn't that a bit like banning cars because some people can't drive?

Some diagrams are simply not for mass consumption and this is one, particularly because it is designed to illustrate an interpretation of ranges instead of the direct/linear representation of the raw data.

Of course I'd illustrate this fact as a Venn diagram comparing "box diagram" Vs "people" (intersection those who understand it) but I'm afraid the universal set may be mistaken as "those people who don't have eyes" rather than literally everything else.

Perhaps we should stop using that too, since it's non obvious what the universal set is.

All diagrams have some ambiguity and can be misinterpreted, sometimes it's deliberate (e.g. bar chart vertical axis not starting at 0 or scale not being linear) and that's why there's the saying "There's lies damn, lies, and statistics." That doesn't mean some diagrams are not useful, just that it's not suitable for some audiences who may misinterpret the data.

Re: I've stopped using box plots (2021)

#10
No you shouldn’t stop using box plots. You should use them for when they are appropriate - showing location and spread. And not shape! There’s absolutely no information on modality or distribution presented past quartiles and limits.

They are mostly useful for comparing batches not analysing an individual batch.

The author doesn’t know what they are talking about and is telling people as if they do. If he read any of Tukey’s material he might know. But no name dropping is enough clearly…

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