4.3. Accessibility Best Practices for Developing Course Content¶

4.3.1.1. Include Text Alternatives for Non-Text Content¶

For any non-text content, provide text alternatives so that the content can be changed into other forms that people need, such as large print, braille, speech, symbols, or simpler language.

For non-text tests or exercises that would be invalid if presented in text, provide text alternatives that at least provide descriptions of the non-text content. Make sure that all images have useful alternative text that screen readers and other assistive technologies can read. For more information, see Use Best Practices for Describing Images.

4.3.1.2. Provide Alternatives for Time-Based Media¶

For time-based media, including pre-recorded audio or video content, provide alternative equivalent information, such as captions, audio description or pre-recorded sign language interpretation. For more information, see Create Accessible Media.

4.3.1.3. Make Sure Your Content is Adaptable¶

Design your course content so that it can be presented in different ways without losing information or structure. If your content includes specific information, structure, and relationships (such as sequence) that is conveyed through presentation, make sure the same information, structure, and relationships can be programmatically determined or are available in text. HTML is an ideal format in which to publish course content, because it provides semantic elements with implied roles, states, and properties. Users of assistive technologies rely on such semantic elements to effectively and efficiently consume and navigate content. Publish your content in HTML whenever possible.

Make sure your course content does not rely solely on sensory characteristics such as shape, size, visual location, orientation, or sound to be understood by learners.

4.3.1.4. Make It Easier for Learners to See and Hear Content¶

Make the default presentation as easy to perceive as possible, especially by making it easier for learners to distinguish foreground information from the background, in both visual and audio elements.

For visual elements, techniques include making sure the fonts you use are readable, and that there is sufficient contrast between the foreground and background. Do not use color as the sole means of visually distinguishing an element or conveying critical information. If you must create images that contain text, make sure that the text has a font size of at least 14 points and has good contrast with the background. Images of text cannot be scaled or color corrected as effectively as HTML text. Whenever possible, use the default font and color defined in the edX platform, which was designed to be easy to read. If you choose to override default font colors, make sure that the foreground and background colors have sufficient contrast.

For audio elements, make sure that foreground sounds are sufficiently louder than background sounds.

4.3.2.1. Write Simply and Clearly¶

Avoid jargon. If unfamiliar words or phrases are relevant to the subject, explain them when they are first used, and include a glossary with your course materials. When you use an abbreviation or acronym, provide the full phrase the first time it appears. For example, “World Health Organization (WHO).”

The Center for Plain Language provides detailed resources on writing clearly and concisely, in language appropriate for your content and target audience.

4.3.2.2. Make Your Course Easy to Navigate¶

One aspect of making your course understandable is making sure that learners can easily grasp its structure, find content, and determine where they are within the course.

Name your course sections, subsections, units, components, and discussion topics in a consistent way, and make sure the names are useful and easy to skim. Make an element’s name descriptive of its content, and put important keyword information first in the name. These names are used in navigation menus, page headings, and section headings; they are signposts that help learners to navigate your course and read course content.

When you create written learning resources, break text into sections using HTML elements such as headings, paragraphs, and lists. Long blocks of unbroken text are a barrier to most readers. Segmented content is more inviting and is easier to navigate and search. See Use Best Practices for HTML Markup for guidance on creating accessible HTML.

When you provide links to external materials, use link text that clearly explains the link destination (for example, “Review the Course Syllabus”). Avoid using constructs such as “Review the Course Syllabus here”, with only the word “here” serving as link text. For links that point to documents rather than web pages, include the document type in the link. For example, “Supplemental Reading for Week 1 (EPUB)”. Screen reader users frequently browse lists of links, or navigate web pages by moving from one link to the next. Ensuring that link text is understandable without surrounding context is important.

4.3.3.1. Images That Are Links or Controls¶

If your image serves as a link to additional content or is an interactive form control such as a button, the value of the alt attribute should describe the destination of the link or the action that will be performed when the user clicks the image. For example, if a linked image of an envelope opens an email program to send an email, a useful text alternative is “Send message”, rather than “Envelope.”

4.3.3.2. Images That Contain Text¶

If your image contains text, the alt attribute would typically consist of exactly the same text as is contained in the image. However, there are a couple of conditions when having an empty alt attribute (alt="") is the preferred solution.

If the text contained in the image is also available in nearby HTML, or otherwise accessible text, including it in the alt attribute would be redundant. In this case, setting an empty alt attribute (alt="") is acceptable. Doing so effectively “hides” the image from screen reader users.

If the text contained in the image is for decorative purposes only and adds no value to the content of the page, an empty alt attribute is also acceptable.

4.3.3.3. Images That Contribute Meaning or Additional Context to the Page¶

If the image is a simple graphic or photograph that provides additional context to the surrounding content, the alt attribute should briefly describe the image in a way that conveys that context.

Consider the following examples of meaningful alt attributes for a photo of the famous stone bridge, Ponte Vecchio in Florence, Italy.

• For a representative image of the bridge included on a page about Florence, a meaningful alt attribute would be “Photo of Ponte Vecchio, a famous bridge and shopping center in Florence, Italy.”
• If the context of the page is about the bridge itself a meaningful alt attribute would be more specific: “Photo of Ponte Vecchio showing its three stone arches which span the Arno River.”
• For a technical diagram, or illustration, on a page about the construction of the bridge the alt attribute would include the details conveyed visually, such as dimensions and materials used: “The Ponte Vecchio is a stone bridge with three arches and a span-to-rise ratio of 5 to 1.”
• For a map intended to provide directions to the bridge, the alt attribute would provide directions as text.

4.3.3.4. Graphs or Complex Visual Representations of Information¶

If the image is a graph or represents a complex piece of information, include the information contained in the image as accessible text adjacent to the image, or provide a link to the information. The alt attribute should convey a summary of what the complex image conveys visually. For example, a line graph that represents the price of a stock over time might be “The price of the stock rises from $45 in January of 2015 to over $76 in June of 2015 with a significant drop of 30% during the month of March.”

Consider using a caption to display long descriptions so that the information is available to all learners. In the following example, the image element includes the short description as the alt attribute and the paragraph element includes the long description.

<img src="image.jpg" alt="Photo of Ponte Vecchio"> <p>Photo of Ponte Vecchio showing its three stone arches and the Arno river</p>

Alternatively, provide long descriptions by creating an additional unit or downloadable file that contains the descriptive text and providing a link to the unit or file below the image.

<img src="image.jpg" alt="Illustration of Ponte Vecchio"> <p><a href="description.html">Description of Ponte Vecchio Illustration</a></p>

4.3.3.5. Images With Unknown Descriptions at The Time of Publication¶

If a suitable text alternative is unknown at the time of publication (for example, a webcam image that updates every 10 minutes) provide an alt attribute that includes as much useful information as possible. For example, “Traffic on Interstate 90 at 5:45 PM June 26, 2015.”

4.3.3.6. Non-Informative Images¶

Images that do not provide information, including purely decorative images, do not need text descriptions. For example, an icon that is followed by link text that reads “Course Syllabus (EPUB)” does not need alternative text.

For non-informative images that should be skipped by screen reading software, include an alt attribute but leave it with an empty value (also known as a NULL alt attribute).

<img src="image.jpg" alt="">

4.3.3.7. Information Graphics (Charts, Diagrams, Illustrations)¶

Graphics are helpful for communicating concepts and information, but they can present challenges for people with visual impairments. For example, a chart that requires color perception or a diagram with tiny labels and annotations will likely be difficult to comprehend for learners with color blindness or low vision. All images present a barrier to learners who are blind.

EdX recommends that you follow these best practices for making information graphics accessible to visually impaired learners.

• Avoid using only color to distinguish important features of an image. For example, on a line graph, use a different symbol or line style as well as color to distinguish the data elements.
• Whenever possible, use an image format that supports scaling, such as .svg, so that learners can employ zooming or view the image larger. Consider providing a high-resolution version of complex graphics that have small but essential details.
• For every graphic, provide a text alternative that provides the equivalent information that a sighted learner would obtain from viewing the graphic. For charts and graphs, a text alternative could be a table displaying the same data. See Use Best Practices for Describing Images for details about providing useful text alternatives for images.

4.3.3.8. Accessible Images Resources¶

• W3C Resources on Alternative Text for Images
• W3C WAI Images Tutorial
• HTML5 - Requirements for providing text to act as an alternative for images
• WebAim provides general guidance on the appropriate use of alternative text for images.
• The DIAGRAM Center, established by the US Department of Education (Office of Special Education Programs), provides guidance on ways to make it easier, faster, and more cost effective to create and use accessible images.

4.3.4.1. Accessible Course Materials Resources¶

• The DAISY Consortium is a global partnership of organizations that supports and helps to develop inclusive publishing standards.
• The EPUB 3 format is widely adopted as the format for digital books.

4.3.4.2. Creating Accessible PDF Documents¶

Not all ebooks are available in DAISY or EPUB 3 format. Portable Document Format (PDF) is another common format for course materials, including textbooks supplied by publishers. However, converting materials to PDF documents can create accessibility barriers, particularly for learners with visual impairments. Such learners rely on the semantic document structure inherently available in HTML, DAISY, or EPUB 3 to understand and effectively navigate PDF documents. For more information, see HTML Markup Resources).

Accessibility issues are very common in PDF files that were scanned from printed sources or exported from a non-PDF document format. Scanned documents are simply images of text. To make scanned documents accessible, you must perform Optical Character Recognition (OCR) on these documents, and proofread the resulting text for accuracy before embedding it within the PDF file. You must also add semantic structure and other metadata (headings, links, alternative content for images, and so on) to the embedded text.

When you export documents to PDF from other formats, it is important to ensure that the source document contains all the required semantic structure and metadata before exporting. Unfortunately, some applications do not include this information when exporting and require the author to add or “tag” the document manually using PDF editing software. You should carefully consider whether exporting to PDF is necessary at all.

4.3.4.3. Creating Accessible Word Documents¶

Many of the same accessibility techniques and principles that apply to authoring web content also apply to creating Word documents.

• Images must have descriptive text associated with them.
• Documents should be well structured.
• Hyperlinks should be meaningful and describe the destination.
• Tables should include properly defined column and row headers.
• Color combinations should be high contrast.
• Verify the accessibility of your document using Microsoft’s Accessibility Checker.

In addition, follow these guidelines when you format Word documents.

• Keep formatting simple. Use headings, paragraphs, lists, images, and captions. Use tables for tabular data. Do not add unnecessary indents, rules, columns, blank lines, or typographic variation.
• Use standardized styles for formatting your text, such as Normal, Heading 1, and Heading 2, rather than manually formatting text using text styles and indents. Formatting text for its semantic meaning and not for its visual appearance allows users of assistive technology to consume and navigate documents effectively and efficiently.

4.3.4.4. Creating Accessible Excel Documents¶

Many of the same accessibility techniques and principles that apply to authoring data tables in HTML also apply to creating Excel spreadsheets.

• Images must have descriptive text associated with them. For more information, see Add alternative text to images and objects in Excel documents.
• Column and row headings should be programmatically identified.
• Hyperlinks in spreadsheets should be meaningful and describe the destination.
• Use a unique and informative title for each worksheet tab.
• Do not use blank cells for formatting.
• Color combinations should be high contrast.
• Verify the accessibility of your workbook using Microsoft’s Accessibility Checker.

4.3.4.5. Creating Accessible PowerPoint Documents¶

Many of the same accessibility techniques and principles that apply to authoring web content also apply to creating PowerPoint presentations.

• Images must have descriptive text associated with them. For more information, see Add alternative text to images and objects in PowerPoint documents.
• Column and row headings should be programmatically identified. For more information, see Specify column header information in tables in PowerPoint documents.
• Hyperlinks in presentations should be meaningful and describe the destination.
• Use a unique and informative title for each slide.
• Ensure that information is presented in a logical order
• Color combinations should be high contrast.
• Verify the accessibility of your presentation using Microsoft’s Accessibility Checker.

To make your content accessible and comprehensible to learners who use screen reading software, start in Outline view and include all of your content as text. After completing the outline, add design elements and images, and use the picture formatting options in MS PowerPoint to include detailed text descriptions of images that convey useful information to learners who cannot view the images. Use the Home > Drawing > Arrange > Selection Pane option to view the reading order of objects on each slide. If the reading order is not logical, change the order of the objects.

4.3.5.1. Accessible Mathematical Content Resources¶

• The MathJax website provides guidance on creating accessible pages using their display engine.
• The DO-IT project from the University of Washington provides guidance on creating accessible math content.
• The AccessSTEM website provides guidance on creating accessible science, technology, engineering and math educational content.
• The Design Science News blog shares information about making math accessible.

4.3.6.1. Simulations and Interactive Modules¶

Simulations, including animated or gamified content, can enhance the learning experience. In particular, they benefit learners who might have difficulty acquiring knowledge from reading and processing textual content alone. However, simulations can also present some groups of learners with difficulties. To minimize barriers to learning, consider the intended learning outcome of the simulation. Is your goal to reinforce understanding that can also come from textual content or a video lecture, or is it to convey new knowledge that other course resources cannot cover? Providing alternative resources will help mitigate the impact of any barriers.

Although you can design simulations to avoid many accessibility barriers, some barriers, particularly in simulations supplied by third parties, might be difficult or impossible to address for technical or pedagogic reasons. Understanding the nature of these barriers can help you provide workarounds for learners who are affected. Keep in mind that attempted workarounds for simulations supplied by third parties might require the supplier’s consent if copyrighted material is involved. If you consider third party solutions, we encourage you to evaluate them for accessibility. The easiest way to do this is to contact the vendor and ask them about the accessibility of their product.

Consider the following questions when creating simulations, keeping in mind that as the course creator, you enjoy considerable freedom in selecting course objectives and outcomes. Additionally, if the visual components of a simulation are so central to your course design, providing alternative text description and other accommodations might not be practical or feasible.

• Does the simulation require vision to understand? If so, provide text describing the concepts that the simulation conveys.

• Is a computer mouse necessary to operate the simulation? If so, provide text describing the concepts that the simulation conveys.

• Does the simulation include flashing or flickering content that could trigger seizures?

  If so, and if this content is critical to the nature of the simulation, take these steps.

  • Do not make using the simulation a requirement for a graded assessment activity.
  • Provide a warning that the simulation contains flickering or flashing content.

4.3.6.2. Online Exercises and Assessments¶

For each activity or assessment that you design, consider any difficulties that learners with disabilities might have in completing it, and consider using multiple assessment options. Focus on activities that can be completed and submitted by all learners.

Some learners take longer to read information and input responses, such as learners with visual or mobility impairments and learners who need time to comprehend the information. If an exercise has a time limit, consider whether the allowed time is enough for all learners to respond. Advance planning might help to reduce the number of learners requesting time extensions.

Some online exercise question types, such as the following examples, might be difficult for learners who have vision or mobility impairments.

• Exercises requiring fine hand-eye coordination, such as image mapped input or drag and drop exercises, might present difficulties to learners who have limited mobility. Consider alternatives that do not require fine motor skills, unless, of course, such skills are necessary for effective participation in the course. For example, instead of a drag and drop exercise for mapping atoms to compounds, provide a checkbox or multiple choice exercise.
• Highly visual stimuli, such as word clouds, might not be accessible to learners who have visual impairments. Provide a text alternative that conveys the same information, such as an ordered list of words in the word cloud.

4.3.6.3. Third-Party Content¶

If you include links to third-party content in your course, be mindful of the accessibility of such resources. EdX recommends that you evaluate third-party content prior to sharing it with learners.

You can use the eReader tool or Adding Files to a Course to incorporate third-party textbooks and other publications in PDF format into your course. You can also incorporate such materials into your course in HTML format. See Creating Accessible PDF Documents for guidance on working with third-party supplied PDFs, and Use Best Practices for HTML Markup for guidance on creating accessible HTML.

4.3.6.4. Accessible Custom Content Resources¶

• Effective Practices for Description of Science Content within Digital Talking Books, from the National Center for Accessible Media, provides best practices for describing graphs, charts, diagrams, and illustrations.
• AccessSTEM provides guidance on creating accessible science, technology, engineering and math educational content.
• The National Center on Educational Outcomes (NCEO) provides Principles and Characteristics of Inclusive Assessment and Accountability Systems.

4.3.7.1. Audio Captions¶

Audio captions are essential for presenting the readable equivalent of audio content to learners who cannot hear. They can also be helpful for learners whose native languages are languages other than the primary language of the media. Synchronized text captions allow learners who cannot hear to follow along with the video. The edX media player displays text captions as links in an interactive area adjacent to the video, which allows all learners to navigate to a specific section of the video by selecting some location within the caption text.

Text caption files start with the text version of a video’s spoken content and any non-spoken audio that is important to understanding the context of the video, such as [BUZZER], [LAUGHTER], or [THUNDER]. If you created your video using a script, you have a great start on creating the text caption file. Simply review the recorded video and update the script as needed. Text captions can be uploaded to YouTube along with the video to create a timed text file in SubRip (SRT) format. Otherwise, you will need to transcribe the video yourself or engage someone to do it. There are many companies that will create timed text captions (captions that synchronize the text with the video using time codes) for a fee. SRT files should be associated with video components in Studio. See Working with Video Components for details on how to associate text captions with videos.

4.3.7.2. Descriptions in Video¶

When you create video segments, consider how you will convey information to learners who cannot see what is happening in a video. Actions that are only visible on screen without any audible equivalent are not accessible to learners who have visual impairments.

For many topics, you can fully cover concepts in the spoken presentation. If it is practical to do so, you should audibly describe visual events as they happen in the video. For example, if you are illustrating dropping a coin and a feather together from a height, you should consider narrating your actions as you perform them. Ask yourself if your video would make sense if the learner were only listening to the audio content, for example while they were driving a car.

4.3.7.3. Downloadable Transcripts¶

For both audio and video transcripts, consider including a text file that learners can download and review using tools such as word processing, screen reader, or literacy software. All learners can use transcripts of media-based learning materials for study and review.

4.3.7.4. Accessible Media Resources¶

Accessible Digital Media Guidelines provides detailed advice on creating online video and audio with accessibility in mind.

4.3.8.1. HTML Markup Resources¶

• Creating Semantic Structure provides guidance on reflecting the semantic structure of a web page in the underlying markup (WebAIM).
• Creating Accessible Tables provides specific guidance on creating data tables with the appropriate semantic structure so that screen readers can correctly present the information (WebAIM).

4.3.9.1. Universal Design for Learning Resources¶

• Delivering Accessible Digital Learning (JISC Techdis) provides a useful overview of an inclusive approach to course design.
• The National Center on Universal Design for Learning provides a helpful overview on Universal Design for Learning.