This content is by Saša Stojić-Ito, an instructional designer from Instructure. To read the entire post, and view videos that clearly illustrate what a difference these pillars make, visit Why Accessibility Matters in Course Design.
7 Pillars of Accessibility are guidelines we use to create accessible content. They encompass: headings, alt tags, descriptive links, color, lists, tables, and closed captions.
Headings are text formatting styles used to communicate the organization of the content within a page. They provide a structure and outline and allow screen readers and other assistive technology to scan the content page just like sighted users.
Alt Text or Alt Tag is a written (short and concise) description of non-text content on web pages. Alt Text/Alt Tag is essential for accessibility as the screen reader will read the description in place of an image and display the description if the image is not loading in the browser.
If the link is posted as the URL address, the screen reader will read a raw link letter/number/symbol by a letter/number/symbol, one by one. Therefore, it is best to describe a link as a descriptive phrase, not a sentence, to avoid confusion. The descriptive phrase should consist of the keywords identifying the item.
Text and color background (foreground) need to have sufficient color contrast. Learners who are legally blind, visually impaired, or have color vision deficiency may not be able to identify text in color, emphasized text, or highlighted portions of the text. Using color as the only way to convey meaning is insufficient to meet accessibility standards. Color can be used to convey meaning as long as that meaning is also indicated in some other way, such as using italics, bold, a symbol, an identifier, etc.
Lists are used to itemize related items. An ordered list may have a numerical or alphabetical hierarchy. An unordered list has no hierarchy and should be bulleted.
A "fake" list is created manually simply by hitting a hard return to a new row or by assigning a number, Roman numeral, or a letter. However, the screen reader will not announce the list or the items in it as a list.
Tables are preferred when the content is more complex and requires organizing data. A table is a systematic arrangement of data in rows and columns.
Table scope identifies a caption (title of the table) and whether the cell is a header for a row, column, group of rows, or columns and rows. A header row is a top row in the table in which the individual cell describes the content in the cells that fall directly below. A header column is a left-most column that describes the content in the rows directly to the right.
Audio and video files must be accompanied by complete and accurate transcripts and closed captioning containing proper punctuation, capitalization, and word matching. Captions provide dialogue or a narrative, and audio descriptions provide a non-verbal explanation of what's happening on the screen.
Captions can be open captions (burned into the video that cannot be turned on or off), or closed captions (on-screen text that can be turned on or off).