Training and Certification

Rubel Khan's Blog

New book: Engineering Software for Accessibility

Posted by Rubel Khan on August 12, 2009

9780735693623f We’re pleased to announce that Engineering Software for Accessibility (Microsoft Press, 2009; 100 pages) is now available as a free download or as a hard-copy book available via Barnes & Noble and Amazon. The book was written by Jason Grieves, a Program Manager on the Windows Accessibility Team, and his colleague Masahiko Kaneko.

Jason had this to say about the book over on the Windows Blog:

Our expectations of software are very high (as they should be!). We expect that the software we use will be reliable, secure, and perform well – we expect the software to “just work.” There are many ways that we experience software, some of us use the traditional input method of keyboard and mouse. I and many other people augment this with accessible solutions such as larger screens, speech recognition, and screen readers.

In Windows we consider accessibility just like reliability, performance, and security to be fundamental to all software in the operating system. Our feature teams create their software to meet these and other core requirements, which combine to create an operating system that meets the essential expectations of our users. In Windows 7 we continued the integration of accessibility requirements into our software engineering process. Accessibility, like the other fundamental requirements, has been planned, designed, implemented and tested in Windows 7.

In an effort to enable software developers to create accessible Windows applications, we wanted to share our process with the community. We have captured this engineering process in a new book, Engineering Software for Accessibility. The book addresses three basic questions:

  • How do you plan for accessibility?
  • How do you design your software for accessibility?
  • How can you implement and test to your software to confirm it meets the accessible design?

You will learn that properly implemented accessibility enables access to Windows applications for users with a variety of capabilities. We are pleased to offer you the ability to follow much of process our engineers used to make Windows 7 the most accessible operating system Microsoft has yet produced!

We’d like to share the book’s Introduction today. We’ll share other excerpts in the future.


What comes to mind when you think of accessibility? If you’re like most people, you might
conjure up images of a wheelchair or perhaps someone who is blind. What about someone
with a broken arm, a child with a learning disability, or a 65-year-old who needs high-prescription
eyeglasses to read? When it comes to technology, accessibility pertains to a
wide range of people with a wide range of abilities, not just the folks with disabilities.

Accessible technology is technology that users can adapt to meet their visual, hearing,
dexterity, cognitive, and speech needs and interaction preferences. Accessible technology
includes accessibility options and utilities built into products, as well as specialty hardware
and software add-ons called assistive technology (AT) that help individuals interact with a

There are essentially two types of users of accessible technology: (1) those who need it,
because of disabilities or impairments, age-related conditions, or temporary conditions (such
as limited mobility from a broken arm), and (2) those who use it out of preference, for a more
comfortable or convenient computing experience. The majority of computer users (54 percent)
are aware of some form of accessible technology, and 44 percent of computer users use
some form of it, but many of them are not using AT that would benefit them (Forrester 2004).

A 2003–2004 study commissioned by Microsoft and conducted by Forrester Research
found that over half—57 percent—of computer users in the United States between the
ages of 18 and 64 could benefit from accessible technology. Most of these users did not
identify themselves as having a disability or impaired but expressed certain task-related
difficulties or impairments when using a computer. Forrester (2003) also found the
following number of users with these specific difficulties:

• One in four experiences a visual difficulty.
• One in four experiences pain in the wrists or hands.
• One in five experiences hearing difficulty.

Besides permanent disabilities, the severity and type of difficulty or impairment an individual
experiences can vary throughout a person’s life. Table I-1 lists the four key classes of disabilities
and the types of accessibility options, utilities, or AT devices your users might use to
address their difficulties or impairments.


By 2010, the number of accessible technology users is expected to rise to 70 million, up from
57 million users in 2003 (Forrester 2004). Among users who use built-in accessibility options
and utilities, 68 percent have mild or severe difficulties or impairments, whereas the remaining
32 percent have no difficulties or impairments (Forrester 2004). Among users who use AT
products, such as trackballs or screen magnifiers, 65 percent did not report health issues as
reasons for using AT products, but rather cited that these products make computers easier to
use, more comfortable, and more convenient, or that they wish to avoid developing a future
health issue (Forrester 2004).

If a majority of your users could benefit from your product being accessible, doesn’t it just
make sense to build an accessible product? If you have decided to do so, you are sending a
message to your customers that their needs matter. Populations in many countries are getting
older. Civil rights for people with disabilities are gradually being extended to encompass
digital inclusion. Governments are requiring procurement officials to purchase products that
are the most accessible (mandated in the U.S. by Section 508 of the Rehabilitation Act). For
technology producers, creating accessible products is just the right thing to do, and it makes
good business sense.

Who Should Read This Book

This book is intended to be an introduction to create accessible software products. If you want
to understand how to incorporate programmatic access and keyboard access into your interfaces
and how accessibility fits into the software development cycle, this book is for you. If
you are a project manager or someone who is overseeing the development of an accessible
product, you should also find this book helpful in understanding how accessibility is integrated
at each stage of the development cycle.

What This Book Covers

As you might guess, accessibility should be integrated from the beginning of the product
development cycle, when the application or product is in the planning or design phase, rather
than later, when retrofitting your product for accessibility can be extremely costly—and
sometimes impossible, because part of accessibility development requires attention at the
architecture level. This book will guide you through the process of planning for the two critical
pieces for accessibility, programmatic access and keyboard access, from the beginning of
the software development lifecycle and integrating it throughout. It is, therefore, suggested
that you first read the chapters in this book sequentially and then afterwards use this book as
a reference as you develop your product. This book will also show you how to map out the
logical hierarchy for your product and plan for implementation using UI Automation (UIA),
Microsoft’s accessibility API, to create products that work with assistive technologies.

Here is what to expect in each chapter:

• Chapter 1, “The UI Automation Environment,” provides definitions and an
overview of UIA and its role in accessibility.
• Chapter 2, “Designing the Logical Hierarchy,” walks you through the steps for
designing a logical hierarchy of your product, which will serve as a model for your
accessibility implementation.
• Chapter 3, “Designing Your Implementation,” guides you through the process
of designing the implementation of the controls in your UI.
• Chapter 4, “Testing and Delivery,” discusses testing for the programmatic access
and keyboard access in your product and documentation for delivery, as well as a
brief summary of steps for incorporating accessibility into your product.

The Basics

As mentioned, programmatic access and keyboard access are two critical pieces to accessibility
and are the basis for this book. Let’s go over these two areas a little further, as well as
some basic information and settings you should be aware of when developing for accessibility.

Programmatic Access

Programmatic access is critical for creating accessibility in applications. Programmatic access is
achieved when an application or library of UI functionality exposes the content, interactions,
context, and semantics of the UI via a discoverable and publicly documented application programming
interface (API). Another program can use the API to provide an augmentative,
automated, or alternate user interaction. Basic information conveyed through programmatic
access includes: navigation, interactive controls, asynchronous changes to the page, keyboard
focus, and other important information about the UI.

Programmatic access involves ensuring all UI controls are exposed programmatically to the
AT. Without it, the APIs for AT cannot interpret information correctly, leaving the user unable
to use the products sufficiently or forcing the AT to use undocumented programming interfaces
or techniques never intended to be used as an “accessibility” interface. When UI controls
are exposed to AT, the AT is able to determine what actions and options are available to the
user. Without proper programmatic access, a user may receive useless, erroneous, or even no
information about what they are doing in the program.

Keyboard Access

Keyboard access pertains to the keyboard navigation and keyboard focus of an application.
For users who are blind or have mobility issues, being able to navigate the UI with a keyboard
is extremely important; however, only those UI controls that require user interaction to function
should be given keyboard focus. Components that don’t require an action, such as static
images, do not need keyboard focus.

It is important to remember that unlike navigating with a mouse, keyboard navigation is
linear. So, when considering keyboard navigation, think about how your user will interact with
your product and what the logical navigation for a user will be. In Western cultures, people
read from left to right, top to bottom. It is, therefore, common practice to follow this pattern
for keyboard navigation, though there are exceptions to this practice.

When designing keyboard navigation, examine your UI, and think about these questions:

• How are the controls laid out or grouped in the UI?
• Are there a few significant groups of controls?

o If yes, do those groups contain another level of groups?

• Among peer controls, should navigation be done by tabbing around, or via special
navigation (such as arrow keys), or both?

The goal is to help the user understand how the UI is laid out and identify the controls that
are actionable. If you are finding that there are too many tab stops before the user completes
the navigation loop, consider grouping related controls together. Some controls that are
related, such as a hybrid control, may need to be addressed at this early exploration stage.
Once you begin to develop your product, it is difficult to rework the keyboard navigation, so
plan carefully and plan early!

Go further: For guidelines on designing keyboard focus and keyboard navigation, go to

Respect Your User

When developing accessible products, a key thing to keep in mind is to respect your end
user’s preferences and requirements. Whether they are selecting larger icons, choosing high
contrast, or using a screen reader, users configure their system settings for a more comfortable
user experience. It is absolutely essential, then, that you allow system-wide settings to
work with your product. Overriding those settings through hard-coding might impede or
even prevent a user from accessing parts of your products.

Visual UI Design Settings

When designing the visual UI, ensure that your product has a high contrast setting, uses the
default system fonts and smoothing options, correctly scales to the dots per inch (dpi) screen
settings, has default text with at least a 5:1 contrast ratio with the background, and has color
combinations that will be easy for users with color deficiencies to differentiate.

High Contrast Setting

One of the built-in accessibility features in Microsoft’s Windows operating systems is the High
Contrast mode, which heightens the color contrast of text and images on the computer
screen. For some people, increasing the contrast in colors reduces eyestrain and makes it
easier to read. When you verify your UI in high contrast, you want to check that controls, such
as links, have been coded consistently and with system colors (not with hard-coded colors) to
ensure that they will be able to see all the controls on the screen that a user not using high
contrast would see.

System Font Settings

To ensure readability and minimize any “unexpected” distortions to the text, make sure that
your product always adheres to the default system fonts and uses the anti-aliasing and
smoothing options. If your product uses custom fonts, users may face significant readability
issues and distractions when they customize the presentation of their UI (through the use of
a screen reader or by using different font styles to view your UI, for instance).

High DPI Resolutions

For users with vision impairments, having a scalable UI is important. UIs that do not scale
correctly in high dpi resolutions may cause important UI components to overlap or hide other
components and can become inaccessible. Since the release of Windows Vista, the Windows
platform replaced large font settings with dpi configurations.

Go further: For more information on how to write high dpi applications, go to

Color Contrast Ratio

The updated Section 508 of the Americans with Disability Act, as well as other legislations,
requires that the default color contrasts between text and its background must be 5:1. For
large texts (18-point font sizes, or 14 points and bolded) the required default contrast is 3:1.

Go further: For more information on checking color contrast, go to

Color Combinations

About 7 percent of males (and less than 1 percent of females) have some form of color deficiency.
Users with colorblindness have problems distinguishing between certain colors, so it is
important that color alone is never used to convey status or meaning in an application. As for
decorative images (such as icons or backgrounds), color combinations should be chosen in a
manner that maximizes the perception of the image by colorblind users.

Go further: For more information on color combinations, go to

How Accessibility Fits into the Development Cycle

Now that we’ve covered some of the basics, let’s talk about how accessibility fits into each
stage of the development cycle—requirements, design, implementation, verification, and
release. You can adapt this model to the development cycle for your product. Figure I-1
provides a comprehensive view of a traditional software development cycle and activities
you can do to incorporate accessibility into your product.



Requirements Stage

There may be a variety of reasons why you may want to incorporate accessibility into your
product for a variety of reasons: you want to create software that’s accessible for a loved one,
you hope to sell your product to the U.S. government, you want to expand your market base,
your company or the law requires it, or you simply desire to do the right thing for your customers.
When you decide to create a new product or update an existing one, you should
know whether you will incorporate accessibility into your product.

Once you have set your requirements, generate personas that exemplify users of varying types
of abilities. Create scenarios to determine what design features will delight and assist your
users, and illustrate how your users will accomplish tasks with your product. Prioritize your
features, and make sure that all users can complete your use cases. Beware of blanks in your
specifications! Your goal is to ensure that your product will be usable by people of varying

Go further: For more information on personas, go to

Design Stage

In the design stage, the framework you will use is critical to the development of your product.
If you have the luxury of choosing your framework, think about how much effort it will take to
create your controls within the framework. What are the default or built-in accessibility properties
that come with it? Which controls will you need to customize? When choosing your
framework, you are essentially choosing how much of the accessibility controls you will get
“for free” (that is, how much of the controls are already built-in) and how much will require
additional costs because of control customizations. If accessibility was implemented in the
past, look at the design docs for those earlier versions to see how accessibility features were
implemented in them.

Once you have your framework, design a logical hierarchy to map out your controls (Chapter
2 covers this topic in more detail). If your design is too complex, or your framework won’t
even support the features that you are thinking of, it may not be worth the time, money, or
effort to develop them. Accessibility can sometimes be a way to measure the usability and
approachability of your product’s overall design. For instance, if you are finding that the
design of your keyboard navigation or logical hierarchy is becoming way too complex, it’s
likely that your user will have a hard time navigating your UI and will have a bad experience
with your product. Go back to the drawing board, and make sure you are following fundamental
user experience (UX) and accessible design practices. It’s likely that somebody has
already addressed the same design issues you’re facing.

When you have designed your programmatic access and keyboard access implementation,
ensure that all accessibility API information is noted in the specs, including all the basic
development settings touched on earlier (settings for high contrast, system font defaults, a
dpi-aware UI, a 5:1 text-to-background contrast ratio, and color combinations that will be
easy for users with color deficiencies to differentiate). Keep in mind that it may be harder (or
easier) to adhere to certain accessibility settings, depending on the framework. Programmatic
access is often limited by the UI framework for the application, so it is crucial in the design
stage to reconfirm the standards and expectations of the accessibility API supported by the UI
framework. Keyboard navigations and the flexibility of accessibility implementations are
usually tied to the architecture of the UI framework.

It is absolutely critical to note that when designing your programmatic access, you should
avoid creating new custom controls as much as possible, because the cost for development,
documentation, and help on how to interact with the control is significant, and ATs may not
know how to interact with the control.

Implementation Stage

In the implementation stage, you will need to make sure that the chosen architecture and
specs will work. If the specs do not work, go back to the design stage, and figure out a more
effective or less expensive alternative.

When you implement the specs, be sure to keep the user experience in mind as you develop
your product. Accessibility personas are great for reminding you of who your users are!

Verification Stage

In the verification or test stage, ensure that all the specs were implemented correctly and that
the accessibility API is reporting correctly for programmatic access. Your accessibility API,
such as UIA, must expose correctly to AT. For testing, use both accessibility test tools and full-featured,
third-party accessibility aids. Write test cases and build verification tests for your
accessibility scenarios to ensure that all the specs were implemented correctly.

Consider leveraging automated testing, and establish a process and metrics for accessibility
bugs. You want to have clear and consistent severity ratings for these problems. Such ratings
may look something like the following:

• High severity means that no workarounds are available for your target users, or the bug
blocks the user from completing the task.
• Moderate severity means that workarounds are available, or that the bug does not block
the user’s ability to complete the operation. Do not overlook moderate severity issues,
just because there is a workaround. These issues can sometimes introduce other,
significant usability or product quality issues.
• Low severity means that the bug’s impact to accessibility with workarounds is low.

The verification stage is a good time to start documenting all the accessibility options and
features of your product. Just be sure to create documentation for your users in accessible
formats! If you hope to sell your product to the U.S. government, you may also start funneling
this information into a Section 508 Voluntary Product Accessibility Template (VPAT), which is a
standardized form developed by the Information Technology Industry Council (ITIC) to show
how a software product meets key regulations of Section 508 of the Rehabilitation Act. You
absolutely want to address any high severity issues before the VPAT process, as any problems
with your product will be subject to VPAT documentation.

Before your final release, be sure to obtain and incorporate feedback from your customers
and partners throughout the development cycle. Include people with disabilities in your
usability studies and beta testing. Work with your usability team to plan for specific accessibility
studies. Include AT vendors in feedback programs, and collaborate with them to ensure
that their products work with yours. Ideally, you should not need to make any major changes
to your product at this stage. Any major (or expensive) changes should be reserved for your
next revision.

Go further: For more information on accessibility tools and declarations of conformance, go to

Release Stage

In the release stage, continue to engage with AT vendors and users. Include accessible documentation
both internally and externally with your product, and collaborate with your
marketing group on go-to-launch activities and external messaging for your product.

Ready, Set, Go!

At this point, you should now have a general understanding of what accessibility is, the types
of AT your users may be relying on to use your product, the basic development settings you
should include in your product, and how accessibility fits into the development cycle. You are
now ready to learn more about the various components in the UIA architecture, how to
design a logical hierarchy, design your implementation, and how to test your implementation
and deliver your product. Through each stage of the process, you will continue to learn how
to set the foundation for accessibility through programmatic access and keyboard access. For
more information on the visual UI design settings mentioned earlier (such as high contrast,
default font, and high dpi settings), which are also necessary for an accessible product, check
out the sample of resources we provide to get you started.

Remember, designing and developing for accessibility is one of the best ways to give you
clarity about the user experience in general. By creating accessible products, you are working
to improve the user experience for all people. The next chapter proceeds with an introduction
to UIA, Microsoft’s accessibility API, which will help you integrate accessibility into your


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