Are you sure the unit of measurement used is that important?

Joe Clark, in his book Building Accessible Websites, argues that web designers should not get overly concerned with the issue of whether text is resizable on the pages they design.

His argument stems from his definition of 'visually-impaired people', as only those who need to use assistive technology on their computers to access the web. Having defined visually impaired people thus, he considers that the units a designer uses to set text on a web page 'are essentially irrelevant to the actual visually-impaired people' [because] ' Accessibility is handled exclusively by the visitor's adaptive technology'. (p 223).

In other words, it doesn't matter what unit of measurement you use, because visually-impaired users will use whatever bit of technology they already have installed on their computer, to magnify, read out, or convert to braille, the text on the screen.

The only people, who will be affected by the choice of unit, therefore, will be 'normal-vision people who find the task of reading that specific page difficult.'(p223). And these people should not be our concern because they are not visually impaired people - and, therefore, outside the remit of accessible web design.

The argument has an attractive logic to it, however, I see some problems with this approach:

Although, I disagree with Joe Clark's approach on this point, I largely support his general approach to accessible web design; and I would recommend Building Accessible Websites.

The other issue that we need to address - and one that can be killed off with less resistance - is that you should use absolute units of measurements to set the size of text on your page. This practice seems to stem from the misguided idea that it is the only way a designer can take complete control over how their webpages will look.

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