I've always hated the data-ink ratio metric. It's totally invalid.
The proof of this is right there in one of the examples in The Visual Display of Quantitative Information.
He shows an example where the axes of a scatter chart are shortened to the range of the data in each direction. This is a data-ink win-win! You get more information (the range of the data, at a glance), and it doesn't matter how little importance that is because you also have less ink!
But of course it actually looks terrible. To think otherwise, you have to be so busy thinking about metrics that you ignore your eyes. The whole thing looks like a soup of visual fragments rather than a single cohesive thing.
Imagine you had several of these on a page side by side. It would be far harder to visually focus on one for a moment, because the fragments of different subfigures would be one big visual soup.
The solution is to put boxes around them (they don't have to be big thick black boxes, just something to visually separate the different things). But of course Tufte hates boxes. They add ink for no information content.
It's just bad science. Or brains don't process black pixels, one at a time, spending mental energy on each one. They see different visual fragments, having been heavily pre-processed by the CNN in our optic nerves before reaching our frontal contexts. The thing you actually need to minimise is visual complexity. Often, adding ink (for no information) helps with that.
I think the idea that a bar chart is usually improved by narrowing its bars while keeping them in the same positions is pretty silly. Yes, the article does say that one can take it too far, but I think that's the wrong framing. It's not that using less ink is good, but sometimes if you take that too far then it competes with visual clarity. Visual clarity is always the goal; sometimes clearer designs have more non-data ink, sometimes less; many designs are too busy so "less non-data ink" is usually good, but not always.
Tufte's "data-ink ratio" is a pretty good heuristic, but e.g. it would probably become a better match for actual visual clarity if what you counted wasn't "amount of ink" but something that measures spatial change in ink. It's the transitions that feel like noise, much more than patches of constant colour. But "data-ink ratio" is easier to say and easier to read than "ratio of integral of norm of gradient of colour".
Also, I think this sort of graph is better with very light gridlines than with no gridlines, though I think Tufte would disagree.
Also also, in Tufte's book, immediately before the section about "data-ink" there is an copy of a graph drawn by Playfair showing a country's balance of trade over time. Tufte gives it as an example of a good informational graphic. You can see it at https://en.wikipedia.org/wiki/William_Playfair#/media/File:P... if you like. This graph uses shading to indicate which direction the balance of trade goes in; that information is completely redundant with the curves by which the shading is bounded; but it would very much not be improved by removing that "redundant" ink even though according to his principles as interpreted by the page linked here that would make a huge improvement in the data-ink ratio.
This isn't a great example, because they're effectively using a chart to show a handful of data points. The key with the data/ink ratio is to densify the amount of data shown so that the ink that is used can show additional dimensions or statistics -- such as using a 2 dimensional plot, turning the axes into box plot equivalents, or other relationships.
There should be a similar metric for information density in an article. This one is so repetitive that it's hard to keep reading since the whole point was already contained in the first section. The rest keeps just repeating again and again. Too bad the slop density is off the charts on this one.
That page is a lot of ink for very little data. It's also somewhat wrong - no, you can't claim the axis marks and labels aren't data ink at all just because it doesn't directly reflect the measure. They are still data that's extremely relevant to reading the chart. Yes, even if Tufte says otherwise.
Meanwhile, even Tufte's advice was explicitly to grey them down, but not completely remove them.
(And we can debate Tufte's advice - lots of other comments on this page how he had great aesthetic sensibility, but his advice wasn't grounded in reason or actual readability research, and so is limited to the examples he chose)
"The data to ink ratio is the ratio of data to ink. The data to ink ratio can be increased by decreasing the amount of ink. Decreasing the ink, while keeping the data constant, will increase the data to ink ratio. Here, we decreased the amount of ink in the diagram, and you can readily see that the data to ink ratio went up. The data to ink ratio should be increased, except when it shouldn't."
To be fair, if someone wanted to present that exact dataset efficiently, they would have probably proposed something much different, like an horizontal chart with thin lines, eg
North [------------] 7
South [--------] 5
East [--------] 5
West [-----] 3
or something, which would have saved a lot of data/ink ratio
You could just remove the bars and present the numbers in a table. In this case I think that would be a considerable improvement (unless the chart is one of several similar charts that one might want to compare, in which case being able to compare their shapes at a glance would have value).
I remember getting Tufte's book ("The Visual Display of Quantitative Information") and being really excited because I'd heard all these great things about it, and then being disappointed because it had no real justification for its claims. The "data ink" thing is a typical example. I'm willing to accept the general concept that many graphs are too cluttered. But there's no particular reason to suppose that quantifying the proportion of "data ink" and trying to optimize it is the best way to handle that. A lot of the book is just taking subjective aesthetic judgements and trying to frame them as some kind of objective truth.
If we really wanted reliable guidelines on how to format graphs, we would want to ground them in psychological research that actually demonstrates that, for instance, some versions result in better understanding or recall of certain information. But as far as I can see Tufte's book makes no attempt to do this. (Perhaps he or those who built on his works did it later on?)
William Cleveland is who you are looking for. He actually did studies like you are looking for on the display of information and its relation to psychological perception. His work is authoritative and predates Tufte significantly. I’m not sure why anyone pays attention to Tufte at all except that he is good at marketing himself. He is kind of the antithesis of quantitative information in that sense. All style and no substance.
Tufte doesn't really move far beyond exploring examples he likes, and as a result, it's hard to take away any generalizable set of principles. Some of the few "rules" like this data-ink ratio are framed as generalizations but depend on idiosyncratic aesthetic judgments.
I think this is why every Tufte-inspired CSS framework or LaTeX style ends up just cargo-culting the style of his books: Bembo/Palatino/ETBook typography, italicized subheads, an asymmetric wide margin layout, margin notes replacing footnotes, illustrations/diagrams in the margins. (Like the linked website.) Few people are really confident after reading the books to stake out their own approach. It's not a bad aesthetic, but if the books were truly successful at their goal, varied application of the ideas would be as common as imitation.
I agree. I think Tufte has good aesthetic judgement and is often right in his criticism of why certain examples of visual data presentation are flawed. But a researcher on this subject he is not.
I've always hated the data-ink ratio metric. It's totally invalid.
The proof of this is right there in one of the examples in The Visual Display of Quantitative Information.
He shows an example where the axes of a scatter chart are shortened to the range of the data in each direction. This is a data-ink win-win! You get more information (the range of the data, at a glance), and it doesn't matter how little importance that is because you also have less ink!
But of course it actually looks terrible. To think otherwise, you have to be so busy thinking about metrics that you ignore your eyes. The whole thing looks like a soup of visual fragments rather than a single cohesive thing.
Imagine you had several of these on a page side by side. It would be far harder to visually focus on one for a moment, because the fragments of different subfigures would be one big visual soup.
The solution is to put boxes around them (they don't have to be big thick black boxes, just something to visually separate the different things). But of course Tufte hates boxes. They add ink for no information content.
It's just bad science. Or brains don't process black pixels, one at a time, spending mental energy on each one. They see different visual fragments, having been heavily pre-processed by the CNN in our optic nerves before reaching our frontal contexts. The thing you actually need to minimise is visual complexity. Often, adding ink (for no information) helps with that.
I think the idea that a bar chart is usually improved by narrowing its bars while keeping them in the same positions is pretty silly. Yes, the article does say that one can take it too far, but I think that's the wrong framing. It's not that using less ink is good, but sometimes if you take that too far then it competes with visual clarity. Visual clarity is always the goal; sometimes clearer designs have more non-data ink, sometimes less; many designs are too busy so "less non-data ink" is usually good, but not always.
Tufte's "data-ink ratio" is a pretty good heuristic, but e.g. it would probably become a better match for actual visual clarity if what you counted wasn't "amount of ink" but something that measures spatial change in ink. It's the transitions that feel like noise, much more than patches of constant colour. But "data-ink ratio" is easier to say and easier to read than "ratio of integral of norm of gradient of colour".
Also, I think this sort of graph is better with very light gridlines than with no gridlines, though I think Tufte would disagree.
Also also, in Tufte's book, immediately before the section about "data-ink" there is an copy of a graph drawn by Playfair showing a country's balance of trade over time. Tufte gives it as an example of a good informational graphic. You can see it at https://en.wikipedia.org/wiki/William_Playfair#/media/File:P... if you like. This graph uses shading to indicate which direction the balance of trade goes in; that information is completely redundant with the curves by which the shading is bounded; but it would very much not be improved by removing that "redundant" ink even though according to his principles as interpreted by the page linked here that would make a huge improvement in the data-ink ratio.
This isn't a great example, because they're effectively using a chart to show a handful of data points. The key with the data/ink ratio is to densify the amount of data shown so that the ink that is used can show additional dimensions or statistics -- such as using a 2 dimensional plot, turning the axes into box plot equivalents, or other relationships.
There should be a similar metric for information density in an article. This one is so repetitive that it's hard to keep reading since the whole point was already contained in the first section. The rest keeps just repeating again and again. Too bad the slop density is off the charts on this one.
That page is a lot of ink for very little data. It's also somewhat wrong - no, you can't claim the axis marks and labels aren't data ink at all just because it doesn't directly reflect the measure. They are still data that's extremely relevant to reading the chart. Yes, even if Tufte says otherwise.
Meanwhile, even Tufte's advice was explicitly to grey them down, but not completely remove them.
(And we can debate Tufte's advice - lots of other comments on this page how he had great aesthetic sensibility, but his advice wasn't grounded in reason or actual readability research, and so is limited to the examples he chose)
It makes me think of https://xkcd.com/688/
A zoom button would have been cool for this one :-)
Ha! Yes. One of my favorites.
That’s interesting. However, with charts, reducing the amount of ink can sometimes compromise readability.
An excellent point that is very well covered in the linked article.
What in the slop?
"The data to ink ratio is the ratio of data to ink. The data to ink ratio can be increased by decreasing the amount of ink. Decreasing the ink, while keeping the data constant, will increase the data to ink ratio. Here, we decreased the amount of ink in the diagram, and you can readily see that the data to ink ratio went up. The data to ink ratio should be increased, except when it shouldn't."
I don't see that text anywhere in the article.
It sounds like you're parodying the article but putting it in quotes is misleading.
How else would you format such a parody?
I think I prefer the 10-12% range myself.
To be fair, if someone wanted to present that exact dataset efficiently, they would have probably proposed something much different, like an horizontal chart with thin lines, eg
North [------------] 7
South [--------] 5
East [--------] 5
West [-----] 3
or something, which would have saved a lot of data/ink ratio
You could just remove the bars and present the numbers in a table. In this case I think that would be a considerable improvement (unless the chart is one of several similar charts that one might want to compare, in which case being able to compare their shapes at a glance would have value).
That's Tufte's first guideline, anyway. Present data in a table unless it's better visualized as a graph.
I remember getting Tufte's book ("The Visual Display of Quantitative Information") and being really excited because I'd heard all these great things about it, and then being disappointed because it had no real justification for its claims. The "data ink" thing is a typical example. I'm willing to accept the general concept that many graphs are too cluttered. But there's no particular reason to suppose that quantifying the proportion of "data ink" and trying to optimize it is the best way to handle that. A lot of the book is just taking subjective aesthetic judgements and trying to frame them as some kind of objective truth.
If we really wanted reliable guidelines on how to format graphs, we would want to ground them in psychological research that actually demonstrates that, for instance, some versions result in better understanding or recall of certain information. But as far as I can see Tufte's book makes no attempt to do this. (Perhaps he or those who built on his works did it later on?)
William Cleveland is who you are looking for. He actually did studies like you are looking for on the display of information and its relation to psychological perception. His work is authoritative and predates Tufte significantly. I’m not sure why anyone pays attention to Tufte at all except that he is good at marketing himself. He is kind of the antithesis of quantitative information in that sense. All style and no substance.
Any book recommendation from William Cleveland on the subject?
Tufte doesn't really move far beyond exploring examples he likes, and as a result, it's hard to take away any generalizable set of principles. Some of the few "rules" like this data-ink ratio are framed as generalizations but depend on idiosyncratic aesthetic judgments.
I think this is why every Tufte-inspired CSS framework or LaTeX style ends up just cargo-culting the style of his books: Bembo/Palatino/ETBook typography, italicized subheads, an asymmetric wide margin layout, margin notes replacing footnotes, illustrations/diagrams in the margins. (Like the linked website.) Few people are really confident after reading the books to stake out their own approach. It's not a bad aesthetic, but if the books were truly successful at their goal, varied application of the ideas would be as common as imitation.
I agree. I think Tufte has good aesthetic judgement and is often right in his criticism of why certain examples of visual data presentation are flawed. But a researcher on this subject he is not.
To your question, I recommend this recent review as one good example: https://doi.org/10.1177/15291006211051956
Viewing in dark mode, so most of the ‘ink’ is used to render the empty background. Every suggested change here decreases the ink/data ratio.
Wouldn't "dark mode" be the equivalent of using black paper? :)
It does exist btw, I've used it before myself.
Paper isn’t ink.