Three strategies of screen reader users

 – posted August 26th, 2008 by John Wood     Comments (2)

The key to designing a good user experience is empathy. Without empathy, design becomes an exercise in interpreting abstract requirements. This problem is particularly prevalent in web accessibility projects, where many members of the team have never seen assistive technologies in use.

Without personal experience of what it is like to use a screen reader, for example, the team are reduced to interpreting vague, context-free WCAG recommendations. I want to go some way towards rectifying this situation in this post by discussing what it is like to use a screen reader and three key strategies screen reader users employ when on the web.

What it’s like to use a screen reader

Using a screen reader drastically reduces the amount of information available to users compared to a sighted person looking at a web page. Screen readers parse the content of the page and read them in sequence, so screen reader users listen to one page element at a time, one after another. This presents an experience that is a lot like an old audio cassette, you can fast forward or rewind, but you are restricted to moving along a line.

In contrast, sight works by building a concurrent mental picture of the page that enables users to hold several disconnected page elements in memory at once and jump directly from one to another. This experience is more like a CD than an audio cassette, as it provides random access to the content. Consequently, sighted users have a (relatively) easier time scanning the page, filtering out irrelevant content, and jumping straight to material of interest.

The three strategies I describe below are ways in which screen reader users cope with or compensate for the slower, serial nature of the web as they experience it.

Page cycling

Page cycling is the basic behaviour I have observed in novice or infrequent screen reader users. Every element on a web page is parsed and arranged in a line by the screen reader, as described above. This line of content wraps on itself, so that when you reach the end of the line you pop back to the start. To a screen reader user, a page becomes one big circular rail that they can cycle around using the TAB key to move to the next element.

While users can move backwards along the rail, I have rarely seen this done in countless hours of user testing. Instead they seem to progress down the page and back to the start, maybe cycling through the page a few times in order to understand it.

A web page experienced this way is like a puzzle. When the page loads, the user has no idea what’s on it and must TAB through most or all of the page to build a first impression. So screen reader users often go through the cycle a few times, building a better picture of the page with each pass.

Speed reading

Strategy two is essentially the same as page cycling, but involves speeding up the rate at which the screen reader reads the page, hence the term Speed Reading. All experienced screen reader users that I have observed employ this strategy. Often, the speed of the reading rate is such that all you can hear is a blur of barely recognisable speech. The MP3 file below will provide you with an idea of what this sounds like.

Listen to a Screen Reader with the speech rate set high

How can anyone make sense of this, you may wonder? Well these users are not trying to listen to any of the content in detail, they are simply listening for keywords. Like all web users, they are on a page for a reason, and in their minds they associate this purpose with one or more words or phrases that they expect to find. They accelerate through all of the content listening for one of these keywords, and if they hear one they stop, slow down and examine that part of the page in detail.

Text mining

The final strategy I have seen used by users of screen readers I call text mining. This uses a function of most screen reading software that allows users to extract links or headings from the page into a separate dialogue box to be read in isolation. You can see my colleague Laurence demonstrate the functionality for extracting page headings in Jaws in the accompanying video.

The idea is that a user may be able to quickly discern the structure and meaning of the content from the headings and the available actions from the links. In practice, many pages are badly structured with poor heading and link text. I have only seen this strategy used by experienced screen reader users.

How knowing these strategies can help

You may be thinking that this is all very interesting, but so what? Well, as I said at the start, empathy makes for better design. Below, I’ve listed some ways in which you can change your pages to help screen reader users employing any of the three strategies I’ve described. But this advice isn’t new, I’ve read it all elsewhere. What I hope is new to you here is a better understanding of why this advice is good advice.

Finally, try using a screen reader to test your pages and be sure to turn your monitor off when you do so. Too many sighted designers check their pages in a screen reader while looking at the page on their screen, so they aren’t getting a true impression of the experience.

Making Page Cycling easier

  • Make sure your page linearises in a sensible, semantic order. Turn off CSS and see what it looks like as long string of text. Does it make sense to encounter the content in this order?
  • Make the path around your pages as short as possible by keeping text clear and concise and by hiding images that do not add to an understanding of the content from screen readers.
  • Don’t waffle, front-load all of the useful content on the page so people can get to it more quickly.
  • Enable people to skip over navigation using skip to content links. Otherwise, they have to listen to every navigation link on every cycle around the page.

Assisting Speed Readers

  • Front-load your headings and paragraphs with keywords that relate to the message of the page and the actions users can take on that page.
  • Use well-structured text, with paragraphs that start with topic sentences and plenty of clear sub-headings.

Assisting text miners

  • Write clear link texts, that contain good keywords and work well even when extracted from their context.
  • Write clear headings, that also contain good keywords and work well out of context.

Categories Accessibility, Usability, Writing for the web

Comments Closed | Trackbacks Off | permalink