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The summary is she is saying you almost always want to show one of two things (and not both): 1) To show the distribution, in which case just the histogram arr
by seanhunter 2y ago
The summary is she is saying you almost always want to show one of two things (and not both):
1) To show the distribution, in which case just the histogram arranged horizontally in the traditional fashion is far better than a violin plot with 2 copies of the histogram vertically and some extra quartile stuff tacked on, especially since lots of standard libraries to do violin plots do kde with very extreme smoothing so the distribution they show can be very misleading as to the real empirical distribution.
2) To highlight the summary statistics (quartiles and median) in which case just the boxplot is better because generally these are hard to read on a violin plot
In case #1 this is usually because the distribution differs significantly from a Gaussian in some interesting way that would make a boxplot irrelevant or misleading. (eg it is bimodal or multimodal).
In case #2 this is usually because the distribution is Gaussian (or otherwise standard) and you want to compare it with other standard distributions. You don't need all the information in the histogram and to include it all would obscure the important point(s) you're trying to make about the median and quartiles. What is considered standard is going to depend a lot on the domain, audience and subject matter. In her case, she's an astrophysicist, so if you're looking at say red shift data from some observation, other astrophysicists will know the distribution you would expect to get from that sort of observation for example.
That video is basically a summary of all the conversation attached to this article in some ways.
- hoseja 2y ago3) They look like THAT
- seanhunter 2y agoWell yes.
- sanderjd 2y agoThis I don't get, they usually look a lot nicer than other visualizations I see. What's the issue here?
- seanhunter 2y agoWatch the video to understand her perspective on this. I don't want to spoil them for you if you like the look and once seen it's hard to unsee.
- sanderjd 2y agoPresumably you're referring to the "it looks like a vulva" thing that some other commenter mentioned, which honestly makes me think I must be trying to give credence to the opinions of people who have not progressed past adolescence, if this is truly their issue.
- seanhunter 2y agoI think you're missing some nuance. She's saying this frequently leads to a situation where she (as a female scientist) is put in an uncomfortable/weird spot by a data visualisation because her colleagues/peers have (in your words) not progressed past adolescence. It seems completely unnecessary to use a data visualisation technique that leads to this issue, especially since it doesn't have any other particular benefit relative to more conventional techniques. In any case - I don't personally use them not because of that but because of the reasons I gave[1] which she also mentions in the video - you usually want to present either the distribution (in which case a horizontal histogram without extreme kde smoothing or quartile info is usually better) or you want to highlight just the summary stats in which case the boxplot on its own (or just a table) is generally better. When I find I want to call out a given summary stat (median/mode/some quantile cutoff) on a histogram it's usually better in my view to just show the cutoff on the histogram and shade the tail (eg you frequently see hypothesis tests as a histogram with the critical region shaded and the CV1 number or whatever called out specifically). [1] and one other which is they are even more confusing in many respects for non-experts than a boxplot so if I was to put one in a presentation or whatever I would find myself spending an undue amount of time explaining the plot rather than making whatever point I wanted to make with the plot which is never a good sign. It would be different for someone who tends to write for/present to fellow experts I imagine.
- sanderjd 2y agoThis is helpful! Is there a different name for the version of this that doesn't include the summary statistics on the same graph? I think seeing the distributions at different x-axis values (in my work, nearly always in a time series), but including the summary statistics is not as important and I agree that it's noisy.
- seanhunter 2y agoVertical kernel density estimation plot maybe? I'm not 100% sure what you mean. It would just be a vertical histogram if you're not doing kde.
- sanderjd 2y agoI just mean the "violin" part - yes, just a vertical histogram, but centered - without including the "hard to read" summary metrics on top of it.