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Friends don't let friends make bad graphs
- crazygringo 3y agoOn the one hand, this all seems pretty great. On the other hand, I think a lot of these "bad graphs" are very intentionally chosen precisely in order to hide the small number of data points, or an underlying distribution that looks suspicious, etc. So it's not so much "friends don't let friends", but more "when you see a graph that chooses to obfuscate rather than clarify, suspect it might be intentional".
- earthscienceman 3y agoNot that you're wrong but researchers are also deeply imperfect. They're rushed, they're given no time to actually improve their work, and the emphasis is entirely on 'good-enough' publications. The number of times I've been involved in a paper where the mentality wasn't "get it out the door, now" is.... zero times. Plots often fail to clarify for the precise reason that clarification takes time and effort and those things are lacking in academia in spades. Are people intentionally hiding ugly details, definitely on occasion? But I don't think it's the primary source of such bad figures.
- defrost 3y agoAll that you said with a heavy dash of good data visualisation is more of a skill and an artform than many people realise. I've had four decades of crunching numbers in a variety of Engineering, Geophysics, and science applications with a hefty amount of public consulting on a variety of applications and of the large population of those good at gathering and recording data perhaps only 20% had that extra talent for good visualisation to convey meaning without distortion.
- ctxc 3y agoAre there resources or good examples you would recommend?
- armagon 3y agoI liked "Signal: Understanding What Matters in a World of Noise" by Stephen Few.
- mif 3y agohttps://www.dataviz-inspiration.com/ https://www.dataviz-inspiration.com/
- frederikb 3y agoI really enjoyed Storytelling with Data: A Data Visualization Guide for Business Professionals by Cole Nussbaumer Knaflic. The author really breaks down the individual elements of good/bad visualizations using case studies with lots of actionable advice. Highly recommended.
- yummypaint 3y agoThere is a book called. "how to lie with statistics" by Huff that should probably be required reading for everyone. It's not very technical and a pretty quick read
- taspeotis 3y agoYeah both AMD and NVIDIA churn out some pretty shit graphs year on year. But! Intentionally!
- spartanatreyu 3y agoDon't forget about Apple
- shepherdjerred 3y agoI would consider myself an Apple apologist, but I can't defend their graphs. They're truly unforgivable.
- rswskg 3y agoGot some examples?
- mbreese 3y agoAny of their performance graphs… none of them include axis labels, so you never really know what they are comparing. All you can see is that the newer chip is “faster” or “more efficient” than something else. You just never know by how much.
- ryukoposting 3y agohttps://qz.com/138458/apple-is-either-terrible-at-designing-charts-or-thinks-you-wont-notice-the-difference https://qz.com/138458/apple-is-either-terrible-at-designing-... among others.
- rswskg 3y agothank you!
- llamaInSouth 3y agolol, no... most people suck at laying out graphs... most cant even label axis
- AmINotARobot 3y agoI for the life of me can not produce good graphs in Matlab... I use it so rarely that I forget all the syntax and when to us hold etc. So now I just export the data and plot it with python to annoyance of my pms...
- llamaInSouth 3y agoI'd say Google it, but Google doesn't find much nowadays
- tgv 3y agoIt definitely happens intentionally and unintentionally in psych literature, certainly the first one. Psych articles report p values over ANOVAs, and they blithely assume everything is normally distributed. For one group, there's absolutely no need to poke the sleeping dog. The other group simply has no idea. They shouldn't be doing research, but their training is lacking, and cheap PhDs aren't that easy to come by, so here we are.
- motohagiography 3y agoI wish friends would call them charts and not graphs.
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- dcl 3y agoI use the word 'plot'. Graph is overloaded in the maths/stats/comp sci/ML/etc space.
- jader201 3y agoIt seems like the distinction is subjective and/or ambiguous at worst, and confusing at best [1]. Some people use them interchangeably (not saying this is correct, but that some people think they mean the same thing). [1] https://english.stackexchange.com/a/43029 https://english.stackexchange.com/a/43029
- airstrike 3y ago> 3. Friends Don't Let Friends Use Bidirectional Color Scales for Unidirectional Data why use colors at all in those examples?
- slhck 3y agoPrecisely this! There's no need to code the same information twice; it just means you have to think more about what the graph shows.
- SiempreViernes 3y agoI think the "examples" are better understood as displays of the properties of the colour scales, not examples of how they are used in the wild. That is to say they aren't examples of when you would use a colour scale at all.
- kergonath 3y agoIn the examples, the colour scale improves nothing. The advice is still good in general. A single variable representation can be improved by using a colour scale compared to just gray levels in a lot of cases. And in these cases, using a bidirectional scale for unidirectional data is bad, and vice versa.
- bertil 3y agoHe is explaining the situation using the length of bars. He doesn't recommend using both at the same time.
- tedunangst 3y agoIronically, I was about ten examples in before I even noticed the tiny good/bad labels.
- splonk 3y agoI also appreciate how some of the examples randomly put the bad examples at the end instead of the beginning. I'm not going to say people with glass houses shouldn't throw stones, but maybe you should walk outside first.
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- fastasucan 3y agoYeah, the figures are to cluttered and have too little space between them. In addition its impossible to scroll through that text and figure out the content by just glancing on the charts - as there are no clear marking of which is good and which is bad.
- giraffe_lady 3y agoThese are still all bad to my eye. Way too much "chartjunk", too many colors for most of them. You simply don't need all those lines. They are easier to read if you put less on them, but carefully. Any edward tufte book is about this and a handful of basic techniques go a long way.
- minimaxir 3y agoThese charts are made with ggplot2, which is based on the grammar of graphics. EDIT: I thought Tufte did it, I was wrong. https://www.amazon.com/Grammar-Graphics-Statistics-Computing/dp/0387245448 https://www.amazon.com/Grammar-Graphics-Statistics-Computing...
- giraffe_lady 3y agoGrammar of graphics is a different guy I think but it doesn't matter what it's based on because they still aren't good! Tufte's whole like, thing is essentially that charts need to be intentionally designed to convey a specific concept to a specific audience via careful choice about what information to present. A library can help you with the shapes but can't automate the decisions.
- minimaxir 3y agoYou're correct, I edited my comment.
- jrauser 3y agoI wrote a talk entitled How Humans See Data that puts several of these ideas, among others, into a coherent framework based on research by Bill Cleveland. https://www.youtube.com/watch?v=fSgEeI2Xpdc https://www.youtube.com/watch?v=fSgEeI2Xpdc
- alexpetralia 3y agoI'm very excited to watch this! I've seen your other talks, which were all fantastic, and highly recommend them others.
- andrei_says_ 3y agoThank you for this
- jbay808 3y agoGreat talk and very well presented.
- jsweojtj 3y agoI've recommended this exact talk many times! It's excellent.
- duckmysick 3y agoThank you for posting this. It was an excellent, well-paced talk. 40 minutes flew right by. The part about three levels of estimation was really eye-opening. Even though it's obvious in hindsight, I didn't make the connection until it was spelled out for me.
- jyunwai 3y agoA great reference for further reading about data visualization is "The Visual Display of Quantitative Information" by Edward Tufte, a classic book originally published in 1983 with enduring relevance today.
- rnburn 3y agoThat's a good book. I'd also recommend John Tukey's classic paper "Some Graphic and Semigraphic Displays", https://www.edwardtufte.com/tufte/tukey https://www.edwardtufte.com/tufte/tukey Tukey was one of Tufte's mentors.
- quietbritishjim 3y agoIt's an interesting book with some really interesting examples (good and bad). I also recommend looking at it. But the central premise the text presents is "maximise the information to ink ratio", which sounds very reasonable but is fundamentally flawed. The problem is that quantity of ink (or, on a screen, number of black pixels) is not the same as visual complexity. By the time your brain is interpreting something visual, it has done edge detection, grouping, and other preprocessing. He gives an example of shortening the axes on a scatter plot to show the range of data, rather than intersecting at the corner. This is win-win because it uses less ink but shows more information. But, when I look at the comparison, it's just obvious that the modified version is visually more complex. It would be especially worse on a complex page with text and a few plots next to each other – the fragments would all visually bleed together. One mitigation to that sort of complexity is to put boxes around large district elements, like an entire plot. But boxes are Tufte's absolute nemesis, in that book and elsewhere. It's surprising that after so many years looking at visual displays he still has that attitude.
- 3abiton 3y agoDo you have alternative book recommendations?
- quietbritishjim 3y agoAfraid not. I only found out about Tufte's book due to a mention in xkcd. Until Randall mentions another book about plots I'm not likely to find one :-) It would be nice to find someone like Tufte that gathered some actual evidence. Like, trying different plots on groups of people to see which find information faster, maybe using eye tracking. Even just subjective surveys might be an improvement on one person's opinion.
- rnburn 3y agoOne other rule I've found helpful is banking to 45 degrees -- it's an easy way to rmake elationships easier to perceive: http://vis.stanford.edu/files/2006-Banking-InfoVis.pdf http://vis.stanford.edu/files/2006-Banking-InfoVis.pdf
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- paradox460 3y agoI still generally attempt to follow the rules established by Edward Tufte in The Visual Display of Quantitative Information. Basically, Tufte used the idea of "ink", classified into two groups, data ink and useless ink. The goal is to have a graph with as little useless ink as possible; where every bit of information visible in a graph (or table) is relevant to the end output. To this extent, he recommended dumping axis lines where unneeded, labels, keys, gridlines, and many more things. LaTeX tables, by default, tend to look like what Tufte proposed, which is probably why LaTeX tables look so damn good compared to the HTML defaults
- TehShrike 3y agoWhile reading chapter 6 of that book, I was inspired to make this digital scatter graph trying to implement his "data-ink maximization" principle: https://tehshrike.github.io/classy-graph/ https://tehshrike.github.io/classy-graph/ It was a good exercise. I really like that book.
- beloch 3y agoA more basic page might serve as a valuable introduction for some. e.g. How many graphs have you seen on evening news programs that don't even have axes labels?
- ppqqrr 3y agoA while ago i had a heated discussion on HN with someone who claimed that any graph where 0 is not the minimum value of all the axes is misleading. We were talking about a graph that shows global temperature rise due to climate change. They claimed the graph was misleading because the Y axis (temperature) didn't start from 0 (fahrenheit? celsius? fucking kelvin?). This person also quipped, "maybe if you can't see if with 0 at the bottom, it's not such a significant change?". That put a dent in my faith in humanity for a while. I'm just glad to see us operating at a higher level. I guess 2016-2020 was a different time.
- ctxc 3y agoYou should hand him a chart with "years" on the x axis with it starting from 0AD. :P
- Moru 3y agoWhy some random starting point like when a religion started counting? Ofcourse you have to start from the beginning of the universe. THAT will put things in perspective!
- SiempreViernes 3y agoThe only sensible start for any time axis is clearly Modified Julian Day 0 which puts the x=0 of any truly god fearing years axis in November 1858, as it should! Alternatively Fermi Mission Elapsed Time is also an acceptably cool zero point, which puts the zero in January 2001. The zero of the unix time is tolerable only in truly desperate circumstances.
- bobbylarrybobby 3y agoEasy solution: just plot the delta in °C since some fixed date. (Or for any graph, just subtract y(x_0) from every point. Tada!)
- lelanthran 3y agoTo add, that's actually a Bett chart anyway, because you aren't showing the temperature over time, you want to show the change in temperature over time. Completely different things.
- baazaa 3y agoNever understood the hate for pie charts when stacked bar charts have a similar problem (hard to compare groups when they're in different positions). If a pie chart isn't good enough, probably switch to a paired bar chart or some other pair-wise comparison.
- kergonath 3y agoStacked bar charts are terrible as well, there is no inconsistency :)
- seanhunter 3y agoThe example for "Friends don't let friends make heatmaps without maxing out outliers"[1] is so common. It's also very frequent in stats visualisations in videogames. If you play strategy or simulation games they often have visualisations to help the player understand what's going on/wrong, but for heatmaps because of the effect of outliers the heatmap gradient is often pretty useless. For example in the game oxygen not included, frequently if you do the temperature viz, everything just turns to either blue or some shade of pinky-red, because if you have a volcano or other heat source all the other colours seem cool. So you can't distinguish between a 1000C volcano and your slightly overheating 270C steam room for instance, they'll just be a pretty uniform shade of pinky red, and your overheating 60C base will be blue because it's pretty cold relative to them. Meaning that heatmap is pretty much useless for diagnosing a bunch of temperature problems. [1] Can't remember the exact wording but that one it's like number 6 or 7.
- mcv 3y agoIf specific temperatures represent a meaningful problem, your colours should be standardised to show those temperatures, and not be automatically generated out of the whole spectrum of temperatures you currently have. In fact, having the meaning of colours change depending on temperature changes sounds like a pretty bad idea.
- kergonath 3y agoMore nuances in the spectrum sounds like a good idea, however.
- nichevo 3y agoWouldn't log-transforming the data be a suitable solution here? Unless monitoring the temperature of the volcano is outside interest, in which case excluding it or marking it as an outlier indeed would be apropriate.
- seanhunter 3y agoOh sure, there's lots of ways you can do it. I'm just saying that people making viz for games often do it in a way that isn't actually helpful, and that's an example.
- tunesmith 3y agoI remember reading a guide a while back, just a web page... from someone who just seemed like they were a master at picking the right graph/chart style for different types of data. He approached it in an exhaustive way by breaking down data into categories and explaining, for each data style, exactly why each chart style and not another one should be picked. I really wish I had bookmarked that guide because it just made it seem so straightforward.
- firecraker 3y agoNice. But I'd add getting rid of heatmaps on large datasets. They are information dense and pretty, but I can't see how anyone interprets them. Better to do clustering and plot the data for each relevant cluster in a more meaningful way. Just a thought
- stared 3y agoQuite a lot of these lessons are not new, see Willard C. Brinton "Graphic presentation" - a book (1939), freely accessible https://archive.org/details/graphicpresentat00brinrich/mode/thumb?view=theater https://archive.org/details/graphicpresentat00brinrich/mode/....
- power_fart 3y agoWriting an "opinionated essay" in a github readme is the most 2023 dev thing I've seen
- tomgp 3y agoThis is a great overview of common mistakes in data viz I will be sharing it with my colleagues. As a good supplement I highly recommend Kennedy Eliot's "39 studies about human perception in 30 mins" https://medium.com/@kennelliott/39-studies-about-human-perception-in-30-minutes-4728f9e31a73 https://medium.com/@kennelliott/39-studies-about-human-perce... ... a whistle stop tour around the research basis for a lot of claims around data viz best practice (esp interesting re the dogma around not using pie charts which seems to be a consistent bugbear of designers going back to the 1930's but around which the research is inconclusive at best) [edit: fixed a typo]
- uolmir 3y agoI hadn't seen that, but I was going to recommend this recent paper: https://journals.sagepub.com/doi/full/10.1177/15291006211051956 https://journals.sagepub.com/doi/full/10.1177/15291006211051... At a glance of the medium article, they seem to have the same perspective on these issues, so the one should complement the other.
- bjoli 3y agoI have never liked violin plots,but I am very much not in the field of data visualisation. Just a week ago I stumbled on a video titled "violin plots should not exist" which made things fall into place: https://youtu.be/_0QMKFzW9fw?feature=shared https://youtu.be/_0QMKFzW9fw?feature=shared
- gullywhumper 3y agoRelated - Kaiser Fung has a long-running blog on bad graphs: https://junkcharts.typepad.com/ https://junkcharts.typepad.com/
- rafd 3y agoAlso: friends don't let friends use line graphs when the data is not continous between the sampled points. (bar graphs are typically more appropriate)