Why Accessibility is Good for Your SEO
Accessibility is the collection of tools and techniques needed to make a website usable by people with physical limitations. These can prevent the use of a mouse or touchpad, or they may make reading the screen difficult or impossible.
Even if your website isn’t mandated to be accessible by government regulations or business requirements, it is still an excellent idea to go through the effort to ensure wide accessibility so that the content on your site is available and easy to use by the surprisingly large number of people who benefit from this technology. About one person in 20 has some sight disability (“low vision” or blindness, for example) and about 8% of the US population cannot effectively use a mouse (there is some overlap here, as blind people generally can’t use a mouse). These are all good considerations for accessibility, too, and for the simple reason that search engines have, in some ways, more severe limitations than any human visitors.
By not taking accessibility into account in your website designs, you could be cutting off 10% of the potential visitors or more—maybe much more if your site targets particular subgroups such as the elderly.
Accessing Accessibility
My goal here is not to talk in detail how to make your websites accessible. You can find a lot of information at WebAIM; their Website Content Accessibility Guidelines (WCAG 2.0) are very useful, and for those that must support the US Americans with Disabilities Act (ADA), they have a detailed list of requirements called out in section 508 of the act, and how to fulfill them.
Another important place to look for information is the World Wide Web Consortium’s (W3C) Web Accessibility Initiative (WAI). As a part of this, they have created the Accessible Rich Internet Applications suite, WAI-ARIA. This adds ARIA attributes that can be placed on HTML tags to describe roles, which come along with certain expected behaviors, and relationships in the web page structure. Drupal 7 already generates ARIA attributes for much of its markup automatically.
For existing sites, there are accessibility checkers. The most commonly recommended one is the WebAIM Web Accessibility Evalutation Tool (WAVE). Both WebAIM and Google offer in-browser accessibility audits for Chrome. Be aware that these tools are not perfect and often have false positives. That’s not an excuse for ignoring them, however; rather, you will need to do some digging on the reports to ensure that you’re not overlooking a problem.
The basic idea, however, is that your visual design should have enough contrast so that people who are sight impaired can still see it, those that are blind can use a screen reader to understand it, and those that can’t use a mouse can still reasonably navigate it with a keyboard.
Especially if you start out your design with accessibility in mind, you will find that it is often easier to create a website that is accessible, as long as you don’t stray from using standard controls and conventions in your design. Hint: many able visitors find custom controls and complex navigation unintuitive and difficult to figure out, too. Studies show that visitors are often easily frustrated and will go somewhere else if they find a site difficult to use.
SEO Rationale
As a web professional, you are certainly aware of the importance of Search Engine Optimization. SEO is a collection of tools and techniques to make your site’s purpose and content clear to the web search engines—in particular, Google. In turn, Google’s goal is to provide the best search results it can to the billions of requests it receives. If Google fails at this—whether the results are not well chosen or because Google returns paid ads instead of real results—people can easily go to a competitor. And because the competition is stiff, Google (and the other engines, too) must work to keep up their reputation.
On the other side of this coin is the cottage industry of consulting firms that try to game the system. First we had <meta> tags for keywords and descriptions, but the “black hat” SEO community quickly built pages with these tags that were larded with interesting but unrelated keywords. Then in-bound and out-bound links became important, but the bad guys set up “link farms”—servers running websites whose complete rationale was to have links—again with interesting keywords, that pointed off to clients’ sites. The technology has advanced, but the battle continues to this day.
Caught up in this battle are the vast majority of websites. When Google calls the tune, websites must dance to it or lose out on search directed traffic. Websites need to be constructed so they exude “real” information, however that is defined by Google any given week.
SEO techniques are intended to inform the search engines what our pages are about. That’s why SEO guidelines suggest choosing relevant page <title> text, writing articles in a way that gives a summary of the topic near the top, using semantic markup and other techniques that allow the search engines to get right to what's important.
Your Chocolate in My Peanut Butter
These are all good considerations for accessibility, too, and for the simple reason that search engines have, in some ways, more severe limitations than any human visitors. Search engines can’t “see” the content displayed on the screen, so they don’t “know” that something is hidden or placed out of the viewport. They can’t view images and video and can’t hear audio. They can only render pages and try to interpret the resulting DOM (the internal structure of the page), looking for meaning. This is analogous to a screenreader, indicating headers and links, reading the alt text on images and reading the content.
Because they have similar problems, the solutions to accessibility and SEO overlap. Taking a general approach to accessibility will naturally guide you to many good SEO practices. Both accessibility and SEO are improved by:
- Choosing human readable page URLs and
<title>s - Using only one
<h1>on a page - Using HTML 5 semantic markup tags like
<article>,<section>,<aside>and others (fortunately, Drupal is already doing a lot of this for you) - Only using headings as headings and using them in an heirarchical order that makes sense
- Giving good link text with
<a>tags - Including descriptive
alttext with each image - ...and so on.
Visitors with visual disabilities can quickly realize if a page is likely to have the content they want, and they don't have to follow obviously useless links to find that out. Search engines can quickly categorize the content with a high level of confidence.
While it seems that search engines don't currently make use of ARIA attributes, nothing precludes them from doing so, and it makes sense that they might do so in the future. With a deeper understanding of the web page structure and expected behavior, this could allow search engines to more directly interpret web pages and find the relevant content they contain.
From this brief overview, you can see why it makes sense to take the effort to design for accessibility and integrate these features into your site from the start. This has synergistic effects on your SEO efforts as well. It seems likely that accessibility information will continue to be important and may become even more relevant to search engines and SEO in the future.