SEO and Accessibility – Improve One with the Other

SEO Concept

Search engines and assistive technologies, such as screen readers and connected Braille displays, are designed to detect digital content.  Accessibility and SEO go hand in hand. Both search engines and assistive technology rely on digital coding to understand content such as documents and websites on a computer screen. Screen readers and search engines are not human beings, and cannot hear audio content, see pictures, or understand visual elements such as columns, tables, charts, infographics, or even lists.  They both rely exclusively on digital coding to extract necessary information and pass it on to the end-user. 

Marketing departments work to continually improve the visibility of their brand, using a number of techniques to enhance search engine optimization (SEO).  The idea is to provide the correct type of content so when potential customers look up those words and terms, the website appears early in search results. Many marketing experts may be surprised to learn that making a website more accessible to assistive technology can also make a website more appealing to search engines. 

Show and Tell – Describing Images

One necessity of accessibility is making sure relevant images include a text alternative (alt-text) for a screen reader to read aloud to the user. As yet reliable technology does not exist for image identification (although progress is being made!) so all images must be provided with a description that explains what the image is and how it relates to the content.  This includes complex graphics such as charts, graphs, and diagrams. Alternative text also provides another type of content that can be detected by search engine bots. 

Descriptions should include some indication of how the image is relevant to the surrounding text. Don’t describe decorative images like flourishes that divide sections, frames or boxes around text segments, etc. They don’t add any useful information to the content of the page. If a sighted person wouldn’t reference the image for more information in connection with the content, assistive technology and search engines wouldn’t find it useful either.

There is software available that can automatically “identify” images and provide alt text for you, but these robots don’t always understand what they’re looking at and often misidentify what’s in your picture. The misidentified image wouldn’t make sense to those using screen readers, and search engines wouldn’t identify the image as relating to the content of the website. If you do choose to use software that adds alternative text for you, be sure to review it to make sure it’s correct and makes sense in the context of your content.

Alternatively, image captions can be used in place of alt text. They both serve the same function, so don’t use both. Using both alt text and captioning would be redundant for assistive technology since they would likely have close to or the same information.  A person using assistive technology would hear: “Image: Picture of a white cat. Picture of a white Persian cat.” Choose one or the other and be sure the description includes relevant information but not unnecessary details. 

Hidden Messages- Infographics

While infographics (charts, graphs, flow charts, diagrams) are images, they require a lot more description because they convey a lot more information. Alt text usually works best for shorter descriptions since assistive technology can’t skip through them to find necessary information like it can for other text. Instead of alt text, you can create “invisible” text within the coding.

Including “invisible” text for elements like infographics is an easy way for everyone- sighted people, assistive technology users, and search engine crawlers- to get the information they need from the infographic. Infographics, like other graphics, appear as “images” to screen readers and web crawlers, and because they can’t “see,” none of that information is useful. Describing the infographic fully and in detail using invisible text allows the image to be searchable and usable by screen readers and web crawlers while remaining invisible to sighted people who can otherwise read the infographic. The “invisible” text remains in the coding, not as text on the actual page.

If you’re not sure how to use invisible text, alt text can serve the purpose.  And, while alt text or invisible text may be a place to use keywords as appropriate, keyword stuffing should be avoided. 

No Stuffing

There’s nothing wrong with using keywords in an alt text field to describe an image, but only if those words actually do describe the image. Don’t keyword stuff! It’s bad practice for both SEO and for accessibility. Both screen readers and web crawlers just want to get to the point. Be concise and accurate. While keywords should be used in descriptions, they should be part of a cohesive description of the content, not a string of words. Consider what the description will sound like when read aloud because assistive technology users will be hearing that description.

The Importance of Tagging PDFs

Assistive technology and search engines access PDFs as if they are giant infographics. Unlike HTML formatting, which automatically “tags” elements with digital markers that tell the screen reader or SEO bot what the items are, PDFs are often untagged, making them inaccessible to both assistive technology and search engines. There is too much information in a PDF to use alt text, so the best option is to “tag” the individual elements within the document, making sure they are identified correctly, so that items such as tables are labeled and navigable, list text appears as list items rather than a stream of unrelated words, headings are indicated, and unnecessary items (decorative images like boxes, flourishes, and background photos) are hidden. 

The type of PDF matters too – a text-based PDF, as opposed to an image-based PDF, is more accessible to search engines.  Scanned documents or those saved as images cannot be parsed by search engine bots. They appear simply as an unidentified image. However, just making a PDF text-based won’t cut it for assistive technology, and still isn’t optimal for search engines either. Non-text elements like tables, images, or charts still aren’t recognizable to either form of technology. Be sure everything is tagged and thorough descriptions are added.

Listen to This

Captioning and/or transcribing audio and video files on a website is another great way to add more keywords and digital text to a website while boosting accessibility for everyone. Captioning provides text narration in real-time while watching the video or playing the audio recording on its own in a separate file. Captions are great for people who aren’t in an ideal location to watch a video with sound, such as a noisy subway or in a crowded room. 

Transcripts are useful for people want to skip through content looking for a particular piece of information, or who are not interested in watching a video but want access to the textual information.  Captions and transcripts can also be easily translated for those who want to access info in another language. Either way, they provide text alternatives so that assistive technology can access the audio and video files.  In addition, adding captions and transcripts has been proven to boost SEO. 

Some video platforms like YouTube offer automated captioning, but you will need to double-check any automated captions or transcriptions to ensure they actually say what your video or audio says. Speech to text technology is improving at a great rate, but errors still occur.  For example, “Equidox” often appears as “aqueducts” when rendered by text to speech engines.  

Structure – Set up for success

Tagging digital elements appropriately goes a long way for both search engine robots and humans. Headings that correctly identify a hierarchy let people using screen readers scan through the document quickly to find the information they’re looking for in much the same way as a sighted person (think newspaper headlines used to find articles of interest). This also helps search engine crawlers identify the main points of the page. Page titles are important for the same reason. 

The key here, besides providing accurate information, is to tag headings correctly. For the sake of SEO, some content creators may try to tag more than one element per page as H1 to trick the search engines into prioritizing those headings. However, search engine algorithms often catch on to such trickery and will disregard “spammy” headings. More importantly, incorrect heading structure breaks up the hierarchy and makes the website less accessible to those using assistive technology. Too many H1s or other incorrectly nested headings make it difficult or impossible for the user to determine the main point of the page, how the information is organized, and how to navigate to the relevant information. 

Where are We Going? Include a Site Map

To make an even quicker and easier transition between elements on the page, including a detailed site map can enable screen reader users to identify everything on the site at once and navigate to a particular section. Likewise, it can help search engine crawlers make sense of a website and what the most relevant sections are.

Working Together, but Not the Same

Accessibility can certainly help SEO, but the two are not synonymous. Boosting SEO will not in and of itself make your website more accessible. While search engine crawlers and screen readers do use the same cues within code to identify information, they aren’t necessarily looking for the same information. It’s wise to make your content accessible to assistive technology first, which will help protect you from ADA lawsuits and reach those with disabilities, and the SEO will follow.

Reaching Everyone Online

Don’t take our word for it! There have been a number of organizations that have seen their traffic from SEO increase just by making their digital resources accessible to everyone. National Public Radio (NPR) saw their search traffic increase by almost 7% within a few months of adding transcripts to one of their popular programs, “This American Life.” Over the course of a year, the number of unique visitors to their site increased by more than 4%. 

Google also indirectly encourages accessibility to increase SEO. Its Webmaster Guidelines Page outlines a series of best practices that very nearly overlap with WCAG standards. 

There are a number of similarities between the ways assistive technology and search engine crawlers access information on websites. Making your website more accessible to assistive technology will improve your SEO so you can reach more of your intended audience, including the nearly 25% of the population who experience disabilities. 

Want help making your website more accessible? Ask about Equidox consulting services.


"*" indicates required fields

Clicking Subscribe will take you to the Thank You Page.
Lead Source*
This field is for validation purposes and should be left unchanged.


Accessibility Culture

Accessibility News

Company News

General Accessibility Resources

Laws and Regulations

PDF Accessibility Resources

Nina Overdorff

Nina comes to Equidox with years of sales and marketing experience from a variety of industries and holds a BS in Language Arts Education. Nina has a passion for words, storytelling, and information, which she believes everyone should have access to regardless of ability. After spending time as a teacher with a blind student, she became much more aware of the limitations and abilities of web accessibility, and how essential it is to those experiencing disabilities. “Being able to access information equally ensures that everyone has an equal opportunity for education, employment, and success in life.”