Finding the “right” statistics

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  • The personas in A Web for Everyone, like all personas, put a face on data and user research, showing examples of how real people with real disabilities use technology and the web.  But we also wanted to show how these personas fit into a bigger view of the audience for a web site or mobile app, so we also included statistics about how many people are similar to them.

    When we started our research, this seemed like a pretty simple task. All we wanted was some quantitative statistics on disability from a reliable source. It didn’t turn out to be that easy.

    Different methods, different numbers

    First, it turns out that different countries collect disability statistics in different ways, making them difficult to compare and consolidate. We decided to concentrate on the United States, both for consistency and because we could find resources easily.

    The U.S. Bureau of the Census seemed like a pretty solid source. We used the annual Facts for Features  issued on the anniversary of the Americans with Disabilities Act. In 2011, it reported 36 million people with a disability (12% of the population) including:

    • 10.2 million people with a hearing difficulty
    • 6.5 million people with a vision difficulty
    • 13.5 million people who have difficulty concentrating, remembering or making decisions
    • 19.4 million people who have difficult walking or climbing stairs

    Then, we learned that the way the Census reports disability has changed over the years. For example the total number of people with a disability in the U.S. has varied from 33 million to 57 million. Apparently it’s not a simple question to ask, even when experts are asking the questions.

    And it gets even more complex. Advocacy groups use other research sources to estimate the number of people with specific disabilities. The Hearing Loss Association of America, for example, estimates that 48 million adults in the U.S. report some degree of hearing loss. That adds up to 19% of the population.

    How does this apply to UX?

    The simplest lesson is that these numbers are very big. Even if only 10% of the overall population has one type of disability, that’s a lot. Are you prepared to tell your company that an accessibility problem might be making it impossible for 10% (or even 20%) of the audience to use your site? That could be a lot of lost business.

    A more nuanced answer is that disability is not a clear bright line. Like so many other things about human beings, it’s a spectrum.  People not only have different degrees of disability, but are equally diverse in other ways, like how well they use technology to make the web easier to use or their preferences for how to get information. Maybe broader definitions are more valuable in thinking about the audience for a web site or app because it makes a better case for paying attention all the ways a site should support accessibility:

    • Some things are like an on-off switch: your site either has them or it doesn’t. If images do not have alt text, they are invisible to people who can’t see them. If video doesn’t have captions, the greatest audio track in the world is useless to someone with hearing loss.
    • Some are the kind where improving usability and the user experience helps everyone. Clear communication is easier for everyone to understand and can make all the difference to someone who doesn’t read well. Minimizing the effort it takes to interact with a form helps people with limited dexterity or who live with chronic fatigue and pain, and people using mobile phones on the go.

    We shouldn’t minimize the importance of statistics. They are the analytics of public policy and the numbers can matter.  But it’s easy to get caught up in quantifying a problem precisely when the real message is, “It’s big.”

    What we really need to do is start designing for everyone. So no one is left out.

    One Response to “Finding the “right” statistics”

    1. […] Finding the Right Statistics: Whitney Quesenbery discusses the challenges of qualitative statistics for user research, to give people an idea of how personas fit into the larger picture: the audience for your website or web applications. What matters is that designing for everyone ensures no one is left out. […]

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