When it comes to link text the W3C recommendations say: “clearly identify the target of each link” to aid users in deciding weather they want to follow a link or not. A well written article about Links and accessibility goes into more detail about giving all users the context to decide by including description text and download indicators.
Usability testing has shown that site visitors hate unexpected downloads. When there’s no text indication on whether a hyperlink goes to another webpage or downloads a file, visitors can end up downloading a huge file eating up their mobile data allowance and taking focus away from what they were doing. That Links and Accessibility article recommends that the type of download and size be indicated in parentheses after the hyperlink text to aid people on whether or not to follow the link. For example a descriptive link could look like:
Disability Services Annual Report (PDF, 4.5 MB)
Another technique is to add a PDF or Word icon instead of the text of a download link, but it’s important to make sure the icon has descriptive ALT text. Icons added via CSS or other automated techniques can be missed by people user screen readers.
That Links and Accessibility article I reference in this post probably has the best description about why it’s important to let site visitors know what content a link goes to. It also describes why empty links are a bad practice, a link with no text at all gives no context to non-visual users on what the link is for or where it goes.
At Ohio State, a former Arts & Science web CMS contributor trainer (Drupal trainer) from ACS Communications recommended adding PDF indicators on hyperlinks in her adding links accessibility training video on YouTube. Unfortunately the importance of adding ‘(PDF)’ on hyperlinks it’s well known and many significant web projects have over looked it. By researching and writing about this topic I’m attempting to educate others and perhaps make the web a little more usable.
Here are some other accessibility resources from ACS Communications:
Wild, Gian. Links and Accessibility. AccessibilityOz, 2014. Available at: https://www.accessibilityoz.com/2014/02/links-and-accessibility/