To be effective with accessibility metadata, you need to understand both the accessibility metadata tagging and then how these are used within the general area of structured data. This page gives an overview of the resources available.

Accessibility Metadata Resources

There are two guides that give the overview of semantic tagging and then the specifics for the 1.0 accessibility metadata tags. The first guide, Accessibility Metadata Semantic Markup Primer (non-tagged PDF) (docx), gives an overview of semantic tagging and how to apply these tags to content for accessibility. It does not, however, go into detail on all of the property and attribute values and names. These can be found at Accessibility Metadata Project Best Practices Guide (non-tagged PDF) (docx), for metadata-knowledgeable practitioners, where the document gives detailed information on the attributes and their use. The markup examples are available in both the RDFa and microdata encodings. This document is intended for someone who will be implementing the accessibility metadata.

The details of the tags can be a bit daunting, as there are a large number of properties with various subsets that apply for various resource types. We’ve tried to create useful documents and views of this information that make it a bit more approachable by being specific to media types. The Practical Properties Guide is our most recent attempt to show these properties for wide range of content and learning resources, whether electronic or physical. This document is fundamentally an appendix to the best practices guide, but done on the wiki so that we can refine this as we gain experience. This document/wiki is still at the .6 version of the specification. If you find this document useful, let us know on our mailing list and we’ll update it for the 1.0 specification.

Of course, the accessibility metadata specification and examples, both simple markup and live content, are the best place to get the overview. And seeing other implementations, as listed on this page, is very helpful.

Structured Data Resources

If you’re not familiar with the microdata and semantic tagging concepts, there are a number of very useful web resources for this. Each of these comes from a different perspective and may resonate with you.

  • Google has a short but informative overview video: Introduction to Rich Snippets. This is all on their web page on rich snippets. It’s part of a larger area with more resources.
  • Entrepreneur magazine has a short article describing the benefits from an SEO perspective. It’s basic, but gives a good introduction to the concepts.
  • A longer, but thorough chapter of microdata in HTML5 is available at It goes into microdata much more deeply.
  • Doing a search on “microdata tutorial” gets you access to a large set of useful information, primarily as text. If videos reach you better, search for the same string on Youtube. I prefer the two-part video series (about three minutes) on Youtube (1) and (2).
  • Rich-Snippets-Guide_tinySince life on the web is not complete without an infographic, it turns out that there is a very good infographic that gives an overview of Rich Snippets. You may need to zoom in once you link to the page: it is vey long.
  • As you become more expert,’s full hierarchy is helpful to find the objects and properties inside CreativeWork.
  • Also, if your microdata is not showing up, you should look at their guidance for that. This may seem like a small issue, but it is very common.
  • has a getting started guide and FAQ which give a more technical view, but are very helpful.

Microdata authoring tools and tips

We’ve developed a set of useful tools that we use as we do microdata tagging. This is encapsulated in tips for authoring microdata which has specific tools and tips that you can use.