In our efforts to make knowledge accessible to everyone, if we’re not careful, good intentions can cause us to blunder into useless attempts that benefit no one. I was painfully reminded of this recently when I received a request from a university for an electronic version of my book Show Me the Numbers to accommodate the needs of a student who is blind.

By providing a student who is blind with an electronic version of my book, these well-intentioned folks hoped to make it accessible through the use of “reading software”—software that reads text aloud. I explained to them that books about data visualization cannot be converted into a form that is accessible to someone who is blind because much of the content—indeed, the most essential content—is contained in images that must be seen. They responded by arguing that the Chaffee Amendment gave them the right to convert my book into an accessible form, whether I granted them permission or not, so they would remove the book’s pages from its binding and scan them individually to create an electronic version. When I pointed out that the Chaffee Amendment did not apply in this case because the version of my book that they would create could not possibly be accessible to someone who is blind, they chose to ignore my concern.

I wish I could make the content of my books about data visualization accessible to people who are blind, but I can’t, and technology can’t either. Even if technology existed that could convert a data visualization—an image—into a verbal description, that still wouldn’t solve the problem, for a verbal account of quantitative values in a graph is not a substitute for visual perception. The patterns that are revealed in a data visualization and the operations that are enabled by it (e.g., comparing values and patterns) are not revealed or enabled by words.

Good intentions cease to be good when they produce ineffective results. Sometimes accessibility isn’t possible.

4 Comments on “Inaccessible”

By Andrew. September 19th, 2019 at 11:43 am

Recently I read an article about making video games more accessible to people with varying degrees of blindness. Methods include reducing detail or field-of-view, using higher-contrast palettes, even just making the game easier. Obviously a person with no sight would still not be able to enjoy these games, but there are gamers who, while legally blind, can still make out lights and shapes well enough that they may sufficiently enjoy such a game. In some cases these gamers have to sit with their noses right up to the screen, but it works for them.

I could see electronic versions of your books being potentially useful for people with partial blindness. Maybe reading is difficult and so they may use reading software – obviously that won’t help with visualizations. But it seems that with an electronic version one could blow pictures up and modify the contrast, even put their faces right up to a backlit screen. That could be extremely useful to some people.

By Stephen Few. September 19th, 2019 at 12:46 pm


I understand and agree with the rationale that you just explained for making PDF versions of my books available to people whose sight is only partially impaired. If an enlarged version of a visualization makes it possible for them to see the image clearly enough, then a PDF is useful. I’ve always happily provided PDFs of my books for students with such a disability. I support what’s useful but resist nonsense.

By Kenneth Tyler. December 2nd, 2019 at 2:35 pm

Braille graphs? I know work has been done on translating visual images to a grid of sensors implanted in a person’s back, and this allows the blind to “see” the visual imput to the grid. I think it would be an interesting experiment to get some blind people to participate in.

By Stephen Few. December 2nd, 2019 at 5:53 pm

Hello Kenneth,

I’ve never heard of this research. If you have a link to information about this, please share it with us. I’m finding it hard to imagine how a grid of sensors implanted in a person’s back could simulate the perception of anything but an extremely crude image.

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