In many companies, usability and accessibility are unnecessarily treated as separate, unrelated disciplines. Not appreciating the commonalities between usability and accessibility has created redundancies in skill sets, inefficiencies in data collection, and missed opportunities for usability and accessibility professionals to increase the value of their contributions to the projects on which they work. This article presents an approach to integrating these two highly related endeavors, including examples for what does and does not work along the way.
Inclusive Design: Where Accessibility and Usability Intersect
Accessibility evaluations identify barriers that prevent a person from using a product or service as it was intended. Accessibility evaluations are typically performed for two reasons: to document a product or service’s conformance with legal requirements, and to understand how to improve access for people with disabilities. Products and services need to consider accessibility so that those with functional limitations can participate in society, have access to a greater range of careers, and live independently.
Usability evaluations expose flaws in design that prevent users from correctly or efficiently using a product or service. Usability evaluations are usually performed to increase user interaction efficiency, ensure that the product or service is intuitive or easy to master, and measure the degree to which the user is satisfied with the experience of interacting with the product or service. In order for a product or service to offer the greatest value possible to its intended users, usability evaluations are necessary.
Accessibility and usability intersect in the goals of inclusive or universal design. According to the National Council on Disability, inclusive design aims to create products and services that are “inclusive, accessible, and usable by everyone, including people with disabilities.” In order to achieve inclusive design, accessibility and usability must be integrated.
The motivations for integrating accessibility and usability are numerous. In 2004, the U.S. Census Bureau estimated that there were 37 million people with moderate to severe disabilities and an additional 19 million people with significant functional impairments that impact their ability to work or perform routine tasks. As the average lifespan of the global population increases, these figures are likely to grow as functional limitations become more prevalent. According to the Center for Disease Control, one in five people in the U.S. has some form of doctor-diagnosed arthritis, which is the leading cause of disability. Coupled with the trends for people to age in place and stay in the workforce longer, it is clear that usability and accessibility of products and services will become increasingly important. As accessibility barriers are removed, people with functional limitations will begin to demand usability improvements as they exercise their purchasing power. Companies that fail to integrate accessibility and usability programs will not be able to address emerging usability concerns.
Accessibility Evaluation Exposes Usability Issues
Usability issues can be easier to identify when participants with disabilities are included in the test population. Usability issues that may be an annoyance for someone without functional limitations can prove to be a complete barrier to someone with a functional limitation. The usability issue is easier to detect because the impact on performance is profound.
For example, in a recent evaluation of a water bottle, removing the bottle cap for the first time was difficult or impossible for people with arthritis. The cap was difficult to grip, forcing them to overcompensate and grasp the cap so tightly that they experienced pain in the finger joints and base of the thumb. Testing with the general population indicated a slight annoyance with the cap design, but no real performance issues were detected until several very specific scenarios were introduced.
In one of the scenarios, the water bottles were placed in a cooler full of partially melted ice. Participants from the general population were asked to reach in, select, and open a water bottle. When their hands became wet, their performance and satisfaction ratings dropped to levels consistent with the population of people with arthritis. Many more individuals without functional limitations, in many different scenarios, were required to arrive at the same results as the eight individuals with arthritis produced. Performing the accessibility evaluation first could have directed us to be more specific in how we tested usability in the general population.
Evaluating Both Saves Money
Perhaps the most important reason to integrate accessibility and usability is cost. Most usability professionals have the tools and skills needed to perform accessibility evaluations. Both accessibility and usability professionals know how to plan, conduct, and analyze user data, and both know how to apply and interpret heuristics in the evaluation process. If accessibility and usability teams are staffed separately, there is a tremendous overlap in the skills of the teams. By tasking a single team with both concerns, both usability and accessibility can be evaluated and improved with a smaller total number of employees.
The argument is even simpler for companies that produce electronics and information technologies (E&IT) that are marketed to national governments. In order to compete, many companies that market E&IT to governments have developed accessibility program offices or, at the very least, selected an accessibility champion responsible for disability legislation conformance and documentation. The same companies often have staff trained on usability issues. Successful companies are learning to leverage the two departments to meet government guidelines while simultaneously improving the marketability of their products to everyone.
In the United States, for example, if a company provides E&IT to the federal, state, and/or local governments that have incorporated the technical requirements of Section 508 of the Rehabilitation Act, a usability professional can directly point to lost revenue resulting from a Section 508 disqualification as evidence for the need for additional responsibilities and resources for inclusive design. Usability professionals, by promoting inclusive design, can get involved earlier in the design process to exercise greater influence on decisions that impact the user experience for everyone, including people with functional limitations.
Inaccessible is Unusable
A product can be accessible but not usable. A person with a disability may be able to physically interact with a product or service, but may find the interaction unpleasant or inefficient. Indeed, a product or service can be equally unusable by people without disabilities as it is for people with disabilities. However, the converse is not true. A product or service cannot be inaccessible and usable at the same time.
Barriers to accessibility must be removed before a product or service can become usable to someone with a functional limitation. Therefore, it doesn’t make sense to talk about the usability of a product or service to someone with a disability before the accessibility issues are identified and addressed. If accessibility and usability are not integrated, attempts to measure usability in people with functional limitations are doomed to fail—if they are even attempted at all. The first step in a usability evaluation for people with functional limitations is to ensure that accessibility barriers are removed. The remaining part of the article discusses tips for usability professionals on how they can incorporate accessibility in their research.
Learn about People with Disabilities
While you will never truly understand what it means to be disabled without experiencing the disability, you can learn as much as possible about the experience of someone who is disabled as it pertains to your field of study. To effectively evaluate design you need to be able to see the product or service through the lens of another person’s experience. You will be more effective if you can learn about what it means to have functional limitations. Try using the assistive technologies that people with disabilities use to interact with the product under evaluation. Disability simulation kits, while of limited use in actual evaluations, can give you an enhanced perspective of the issues that people with disabilities encounter.
The variability within the disability community can be overwhelming at first. Disabilities can be permanent or temporary, they can be present from birth or recently acquired, they can involve various sensory, physical, or cognitive abilities, and they can be present in multiple combinations. An individual’s life experience and education can further segment the population. It is helpful to think of a disability in terms of the degree of limitation for a particular functional ability.
Learn How to Interact Efficiently with People with Disabilities
Disability advocacy groups and local disability employment centers can be a valuable resource for usability professionals who want to learn how to interact better with people with disabilities. People with disabilities want the same things as everyone else: they want to be included in the process and treated with respect. Usability professionals should take time to understand how to communicate effectively with research participants and how to arrange the evaluation environment to accommodate a participant’s needs. Use person-first language. Instead of referring to someone as a “blind person,” refer to them as a “person who is blind.” Don’t assume that you know what the person can and cannot do. If you don’t know, ask. It is okay to ask someone if they need assistance, but you should wait for their acceptance of your help before helping. Disability advocacy groups often publish advice on how to interact and communicate effectively with various populations.
Become Familiar with the Tools that People with Disabilities Use
Learn the various assistive technologies and aids commonly used by people with disabilities. A reach aid or manipulator stick is commonly used by individuals that have lower or upper mobility limitations. Screen readers or screen magnifiers may be used to navigate software or websites by people with visual limitations. Understanding how and when each of the tools is used will help you plan for how to accommodate their use in evaluations.
Look for Synergies Between Accessibility and Usability Evaluation
If the same professional is responsible for both usability and accessibility evaluations, it is important to understand the dependencies. Usability evaluations should not be conducted with people with disabilities until after accessibility evaluations have been performed and the results have been incorporated into the design.
If accessibility and usability evaluations are conducted by different teams, it is still important for each team to work together. Accessibility evaluations will likely uncover a number of usability concerns that should be shared with the usability team. The use cases or scenarios developed by the accessibility evaluation team for user evaluations can likely be reused with little or no modifications by the usability team. Learn to leverage each other’s efforts, and start working together to improve the product or service under evaluation.
Understand the Technical Requirements and Standards Related to Accessibility
Usability professionals should become familiar with accessibility heuristics. Many years of usability research have led to the development of a wide variety of usability heuristics. While usability professionals will probably agree on the most useful heuristics, in reality there isn’t a common consensus on the standard set of usability heuristics to apply to most products and services. One mark of an expert usability professional is knowing when and how to apply the myriad of usability heuristics to obtain a certain goal.
With accessibility evaluations, the heuristics are most often the technical requirements of the pertinent disability legislation. Accessibility evaluations rarely go beyond the legal requirements to include other relevant standards and guidelines; however, the standards and guidelines are often based on limited data and are subject to interpretation. It is critical to understand both the letter and the intent of relevant accessibility heuristics.
Develop a Combined Style Guide or User Interface Requirements Document
By far, the most effective way to have an impact on usability and accessibility of a product or service is to be involved early in the design process. By the time the project is in a stage that supports usability or accessibility evaluations with users, it may be too late to make fundamental changes in the design. One of the most useful tools that a usability or accessibility professional has to influence design is to develop a user interface requirements document or style guide based on critical usability and accessibility principles.
Include People with Disabilities in Usability Evaluations
After a design iteration has been performed to remove barriers to accessibility, design the usability evaluation using the results of the initial accessibility evaluation to focus attention on potential problem areas. Recruit both members of the general population and people with disabilities. The evaluation should accommodate the common tools and assistive technologies used by people with disabilities. The usability issues that are found by incorporating people with disabilities in the evaluation process should be bundled and prioritized with the usability issues documented for the general population.
While the focus of this article is on how usability professionals should expand their capabilities to include the ability to perform accessibility evaluations, the argument can be made that accessibility professionals need to incorporate usability evaluations into their work. Years of usability research and technique refinements have led to the establishment of trusted knowledge elicitation techniques and research methods that accessibility professionals should consider using in their research. Usability and accessibility professionals share a common goal: to improve design so that the product or service is a more natural match for the target audiences’ abilities. Integrating usability and accessibility will enhance both practices and result in better user experiences.将可用性和可访问性专业人员划分为两个阵营的做法让这两种职业都深受其害，而且完全没有必要。