The WebAIM organization recently published results of a screen reader usage survey with 1121 responses.
I do have a summary below, but I recommend reading the WebAim results since they have their own interpretations to add.
Platform/Browser
1. The survey confirms the generalization that almost all screen reader users (mostly visually impaired) are on the Windows platform. The two most popular screen reader packages are Jaws (74%) and Window-Eyes (23%).
2. As might be expected, most prefer Internet Explorer (only 2/3 have upgraded to IE 7), but many are also willing to use Firefox.
Navigation
1. About 3/4 of reader base used lists of header tags (e.g. Outline of H1,H2, etc) as a navigation device. Since header structure also improves search engine rankings, this is one of the most powerful tools in the Standards arsenal.
2. Users will look for a search function once they have skimmed the home page. Frighteningly, 61% just jump to the first form field and hope it’s search. Site Maps are not widely used (although they are good for search engine rankings).
3. Skip links are used by a healthy percentage of the user base (38%), so may be worth implementing. When asked for a preference, most wanted “skip to content” instead of “skip navigation”
Which Technology is “Difficult”
- Flash is considered “difficult” by 72% of respondants
- Pop Up windows are “difficult” by 53% of respondants
- PDF is labeled “difficult” by 48% of respondants
- Frames are labeled “difficult” by only 27% of respondants
Labeling Images
1. Another surprise is that 59% do want “atmospheric” images described, but I suspect that context is important.
2. If a photo is of the “White House” it should be identified as “Photo of White House” (80%) instead of just “White House”. Results are more mixed for logos.