Numerous guidelines exist for creating and supporting content that is accessible to people with disabilities, on and off the Web. When these guidelines are supported in the entire web ecosystem, content creators can author accessible content, and expect the accessibility features to be made available by user agents, including assistive technologies when needed. Authoring tools support creation of accessible content, and accessibility features survive transmission to different systems or conversion of content to different formats.
Nearly all of these accessibility features depend on support in some form from the technology in which content is encoded, transmitted, and sometimes transformed. But there is not yet a set of well-documented guidance for such technologies. Instead, requirements are inferred from authoring and user agent guidelines. This makes it complicated for technology creators to ensure they have met the full set of needs. Review from accessibility specialists is limited by bandwidth and expertise, so does not fully address that problem. As a result, varying technologies provide various levels of support with varying levels of compatibility with other technologies. These issues at the core layers of Web technology impact the progress that can be made from support of higher-level guidelines.
Web Technology Accessibility Guidelines aims to fill this gap. It is intended to be a single, well-considered set of guidelines addressing specifically the features technologies need to provide to support accessible. These guidelines relate to the requirements of other guidelines but should not be confused with them. The goal of WTAG is to provide a single source of guidelines for Web technology accessibility. They relate to other guidelines and documentation to provide additional information and rationale for the requirement, but are intended to be a self-sufficient set of guidelines that technology creators can follow.
The primary audience of WTAG is creators of Web technologies. Most of the guidelines relate to content and presentation technologies like HTML, CSS, SVG, PDF, audio/video formats, etc. Some guidelines also address data formats, interchange formats, transmission protocols, etc., usually aimed at ensuring these technologies preserve the accessibility features of content impacted by these technologies. Because of this broad set of relevant technologies, all Web technology creators are considered part of the audience for WTAG.
Secondary audience include creators of higher level accessibility guidelines and other advocates for web accessibility features. Because WTAG has a strong grounding in user needs, researchers and advocates who identify the accessibility requirements of web users with disabilities are also an important audience.
Web Technology Accessibility Guidelines is a product of the World Wide Web Consortium and as such targets only the accessibility requirements of web technologies. Many of the user needs are the same for web use and non-web use, so WTAG will necessarily overlap and hopefully be compatible with similar guidelines addressing non-web space. Nonetheless, WTAG is not designed to be used for non-web technologies and there could be key differences. Furthermore, there are user needs that exist outside the web that do not impact the web, and those needs are completely unaddressed by WTAG.
In spite of these caveats about the scope of WTAG, this scope will evolve as the Web does. More and more technologies are becoming part of the Web, and bringing user needs to the Web along with them. For instance, strictly hardware accessibility issues may be non-web requirements, but the Web of Things brings many of these issues closer to the Web than in the past. WTAG will need to reflect this evolution, and future versions may be required to address user needs that are new to the Web.
The goal of WTAG is to help ensure that web technologies meet the needs of users with disabilities. To do this, the work involves three stages:
The first step in the development of these guidelines is to inventory known user needs. Many user needs affecting web content accessibility are well known and documented in multiple places. These needs are collected and related to each other in order to arrive at a single set of known needs. Sources examined in the development of these guidelines include:
Note the goal of this exercise is not to supplant other good work in this field. The aim is to assemble disparate sources if knowledge about user needs in one place, to facilitate analysis. This work is likely to spin off from the core work of developing WTAG. If another organization creates a sufficiently rich collection of documented user needs it will be possible to use that resource rather than reinvent the work in W3C.
The second stage in development of the guidelines is to identify ways these needs can be met. There are three high-level ways user needs can be met:
These are not mutually exclusive categories. A given user need could be met by more than one of these categories, but the ability of a given category to meet a user need implies the need for guidelines targeting that category. In policy setting and evaluation there may be a preference hierarchy for how best to meet needs, e.g., user agent support of standard features is preferred, but author technical override is needed if user agent support is lacking.
Some needs can be met with present technology only via one of these routes. Other needs can be met by more than one route, and for content to be accessible it is only required that one of the available routes be implemented. Many needs, however, require more than one route to be implemented together for the need to be met. The most common example is that a technology provides a feature, the author uses that feature in the content, and the user agent makes the result available to the user.
All of these ways of meeting user needs are identfied, along with their relationships to each other. Once these approaches are identified, the result is separate lists of requirements for content technologies, authors, and user agents. The relationship among the routes may play a role in prioritization of guidelines, since needs that can only be met by one route may be more important to meet by that route, than needs that could be met by other means as well.
From the above analyses, it should also be easy to see where content technology features are required to make it possible to meet user needs. For example:
Not all technologies will address all ways of meeting user needs. For instance, CSS is primarily design-oriented, and HTML is somewhat semantics-oriented. The technology requirements may need conformance profiles or some other way of guiding technology developers seeking to follow them. It may not be easy to state in a general prescriptive way whether a given technology should, for instance, provide a richer design capability to meet a user need or should instead rely on better semantics for assistive technology-oriented content alternatives. A good structure of the technology requirements should help make it clear that some method of meeting a given user need is important. Horizontal review may continue to be important in guiding technology developers through the possibilities.
The set of approaches to meeting user needs that affects technology features becomes the base information for the Web Technology Accessibility Guidelines. (The other two routes, while important to the analysis, are not directly relevant to WTAG but may inform other work.) These approaches are prioritized, organized, and translated into guidelines-type language to become the Web Technology Accessibility Guidelines.
With the above analyses done, it should be easy to see how current guidelines address which user needs. In turn it should be easy to see where current guidelines to not meet user needs, that in theory should be able to be met by activities within the remit of that set of guidelines. This should be important input into WAI 3.0 / WAI 2020 planning.
Identify user needs that we plan to provide guidance on meeting. These should describe the needs of humans as they currently exist (i.e., without significant evolution or cyborgization from early 21st century norms), and therefore is as era-independent as possible with current knowledge. The focus is on the needs of people with disabilities, but because that is sometimes a relative / contextual condition, a significant proportion of mainstream needs will also be identified.
At least two levels of needs may be identified. The first is truly generic needs, requirements users have to access and use content such as perceive and understand it, and should be stable over time. The second layer is needs specific to technologies of the day, such as ability to understand and operate controls. This layer may be understood as an implementation of the generic needs, so may not be classed as user needs in the end. Regardless of its classification, it will be an important component of understanding the space. This level of needs evolves as technology and design patterns do, so needs to be maintainable separately from the generic needs.
Where user needs are suspected but known, related work may expand the inventory through research when feasible. Therefore the set of documented user needs will evolve over time. A given set of guidelines including WTAG, however, can only address needs that were known at the time of development of the guidelines.
This is a draft user needs collection. It may or may not be prove desirable to prioritize needs in order to yield manageable sets. These needs will be cross-referenced to authoritative sources that also express the same requirement.
In the list below, there may be overlap between user needs, and known ways to meet user needs. These will need to be teased out over the course of the project.
This is a preliminary draft to document how user needs are met in various ways.
For each user need, ways to meet it are proposed for:
Other categories may be included later. Many user needs can be met in more than one way. The mechanism to meet user needs in one of the above areas may require support from one or more of the other areas.
User needs need to be analyzed for how they can be met. The following ways of meeting needs are currently understood:
This version of the resource is primarily to show the structure, not yet a comprehensive documentation of how user needs can be met.
The table below shows how two of the user needs identified above might be met by technology features, author implementation, and user agent support. Each row of the table shows a related set of approaches, in which the approach in column depends on successful implementation of the approaches in the other columns for that row. For instance, many author features depend on support from the technology as well as exposure from the user agents. Some approaches to meeting user needs do not require support from others, which is reflected by rows with blank columns. For instance, it is possible for a user agent to meet certain needs with no particular support provided by the technology or author. This layout is preliminary and a more expressive layout is sought.
| User Need | Technology | Content Author | User Agent |
|---|---|---|---|
| Text Alternatives | Provide a mechanism for author to create text alternatives and associate with content | Create text alternative content and associate with primary content using features of the content technology | Expose text alternatives provided by the author |
| Define parseable and semantically rich content encoding that supports automated creation of text alternatives | Encode content using a content technology that is sufficiently rich that machines can create useful automated text alternatives | Create automated text alternative content based on the semantics of the primary content | |
| Color Contrast | Provide color definition features that allow authors to set colors to meet requirements | Use only colors that meet luminosity contrast guidelines | |
| Provide color definition features that allow users to override author-set colors | Provide a feature for users to override author colors | ||
| Provide color definition semantics that allow colors of common object types to be globally remapped easily | Use semantically defined color mappings to allow user global preferences to be easily applied | Support semantically defined color mappings to allow users to define global preferences that are easily applied across a range of content | |
| Provide a feature to allow users to define their own color preferences | |||
| Provide a feature to allow users to request "high contrast" mode | |||
| Provide a "high contrast" mode that overrides author colors |
The content below is merely initial draft content intended to show how guidelines aimed at web technology developers might look. It has not yet been related to the user needs and ways of meeting them outlined above. It serves as initial brainstorming to help demonstrate viability of this set of guidelines.
The following people contributed to the development of this document.
This publication has been funded in part with Federal funds from the U.S. Department of Education, National Institute on Disability and Rehabilitation Research (NIDRR) under contract number ED-OSE-10-C-0067. The content of this publication does not necessarily reflect the views or policies of the U.S. Department of Education, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.