Universal Design for Learning (UDL) has the potential not only to increase access but transform the learning process. However, fulfilling this potential requires careful application of UDL, taking into account the need for flexibility from the very beginning. The redesign of the CAST Website (http://www.cast.org) is a good example of this necessary process.

CAST's Website is its electronic "front door"; it represents CAST on the web and houses its electronic materials. Therefore, CAST wanted to ensure that the design and infrastructure of the site would serve as be models of UDL. In this article, we describe the process of designing our Website in order to illustrate both the principles and the practice of universal design for learning.

To begin, the CAST Website designers asked three questions:
1. What are the goals of the Website?
2. What barriers to learning do web environments present, and what individual differences must we consider in helping visitors overcome these barriers?
3. How will the website be evaluated?

Answering these questions helped us frame our approach to designing an environment that has the inherent flexibility to accommodate individual differences in a learning-supportive way. Here, we take you through our process.

CAST Website Goals
Teachers practicing Universal Design for Learning find themselves questioning the way in which they conceptualize and articulate assignments. This type of questioning is as important for designers of software, CD-ROMs, Websites, and other curricular materials as it is for classroom teachers. Designers must pay particular attention to the goals of the learning experiences they create. In particular, designers must ask what we want our learners (or in this case, visitors) to understand, and how we can maximize support to help these visitors achieve the deepest levels of understanding.

We identified two major goals for our site: (a) to provide visitors with a deep understanding of concepts relating to UDL, and (b) to provide visitors with a deep understanding of CAST as an organization. In the context of these goals, we defined understanding as the ability to "carry out a variety of actions that show one's grasp of a topic and at the same time advance it" (Project Zero, 1998; see http://learnweb.harvard.edu/alps/tfu/about1.cfm).

Barriers to Learning
Once the goals for our Website were defined, we considered the potential barriers that Web-based media present to achieving those goals. Because the visitors to our Website are not limited to particular groups, we knew that we needed to accommodate many different kinds of users who possess different skills, abilities, backgrounds, and who come from different countries or cultures. In particular, we needed to avoid excluding people with disabilities from learning on our site.

The Web is both a boon and a burden in the quest to support learners with individual differences. New technologies such as the Web can greatly enhance our ability to create opportunities for all learners. At the same time, we risk inadvertently shutting out many learners. (See Qualities of Educational Media http://www.cast.org/udl/QualitiesofEducationalMedia355.cfm for more details on the possibilities and problems of designing for different learners on the Web.)

CAST took several steps to ensure that the Website design avoided this risk. As a baseline, we used the guidelines from the Web accessibility initiative (WAI) of the World Wide Web Consortium (W3C) along with CAST's Bobby evaluation tool (http://www.cast.org/bobby) to ensure physical and sensory access to information on our Website. We also went one step further by allowing visitors to set, store, and retrieve their own interface preferences using our site's Interface Tool (http://www.cast.org/aboutsite/InterfaceTool305.cfm). To guide the implementation of access and to go beyond it to support varied learning needs, we used the universal design for learning (UDL) framework, which is based on three systems in the learning brain: (a) the recognition, (b) strategic, and (c) affective systems. This framework seeks solutions to three types of potential barriers: (a) barriers to recognition of the content and concepts within the site, (b) barriers to interaction with and navigation of the site, and (c) barriers to engagement with the site.

Barriers of Information Representation
There is no perfect way to present information to all users. Any means of representing information creates obstacles for some and differential benefits for others. The key to universal design for learning is to provide alternatives rather than a "one-size-fits-all" solution. In this section we consider the kinds of barriers that are inherent in the most common Web displays and present the built-in features in our Website that help to overcome these barriers. Again, the key is to provide alternatives.

Images. Images are prevalent on our Website. For many individuals, they provide an engaging and optimal alternative to text. However, presenting information entirely or only in images would erect barriers for many individuals, especially for those who are blind or who have low vision. On the CAST Website, we have taken care to ensure that the information presented in images is also available in several flexible and alternative formats.
For some individuals, such as those with low vision, the limited size of an image is sufficient to create barriers to recognition or understanding. Because the images on our Website are digital, they can be easily enlarged by various screen enlarger technologies.

For other individuals, such as those who are blind, merely enlarging an image does not make it accessible. Therefore, all images and graphics on the CAST Website have associated Alt Tags. These brief, written descriptors are embedded in the information about the graphic on HTML pages. Alt tags represent the content of the images in text -- for example, "a picture of a cocker spaniel" or "a graph of cost-benefit ratio." The textual descriptions convey the title or gist of the image. Although this text is not directly accessible to individuals who are blind, these Alt Tags can be accessed automatically via screen readers and various commercially available text-to-speech converters. In this way, a visitor who is blind can also know what images and graphics are contained on a Web page.

Alt Tags are rarely sufficient for educational purposes. They inform the visitor about the type of image that is currently on screen, but Alt Tags rarely are able to carry the critical information found within the image. For educational purposes there is a second type of tag, called a Long Description, which we have used for all images on our Website. This tag is also textual, but is intended to contain the key information. For example, "a picture of a Cocker Spaniel showing its long hair, medium build, short tail, and beady eyes" or "a graph of the cost-benefit ratio showing a steep rise at lower ratios followed by a leveling off in the mid range, and a moderate decline at high ratios" provide more information related to the educational purpose of the images.

Text. Conveying information in text presents problems for a fairly large number of people. First, there are problems for those individuals who are blind or have low vision ­ they cannot see the text or cannot see it in the sizes, colors, or fonts that are typically used by fully sighted designers. With the Interface tool (http://www.cast.org/aboutsite/InterfaceTool305.cfm) on the CAST Website, it is possible to change display variables such as the color of the background, the text, and the highlighting to reduce visual barriers caused by color. To reduce barriers caused by text that is too small, the web browser controls offer the power to increase or decrease the font size. The Interface tool also provides visitors with the ability change the font style.

For individuals who are blind, manipulations of the interface will not suffice. However, these individuals can take advantage of other options. Because the text of the Website is in electronic format, it can be read with a screen reader. An invisible link at the top of every page (a link only a screen reader will find) allows the user to skip the tool column and start reading the page contents.

Individuals may have a variety of other difficulties with text. Persons with dyslexia, individuals for whom English is a second language, or individuals for whom reading is not automatic benefit from the various stand-alone or Web-based applications that translate text into speech. CAST's own e-Reader is an example of this type of technology. This browser enhancement can represent text as speech. It offers a means to read words and highlight them at the same time, which is of great value to users whose difficulties with text are not visually-based.

Language . Language conveys information via text, speech, or sign. However, text, speech, and sign are still language. For some individuals, the language itself may be a barrier to learning from the Website. Visitors to our site have different levels of facility with English and with language in general.

To reduce the barriers inherent in language, our Website provides a Language Tool (http://www.cast.org/aboutsite/Language304.cfm). To accommodate differences in individuals' abilities to comprehend the specific nomenclature of UDL or English in general, the Language Tool provides support for semantics. It will provide a definition for any highlighted word, and it also contains a glossary of important terms and definitions of these terms in context. The Language Tool also allows the user to select a word and find its equivalent in any one of six languages.

Sound (video or audio). Sound (on the track of a video or as an autonomous sound file) can be an excellent method of communication for some individuals. However, for others, (e.g., persons who are deaf) this method of communication is not effective. Thus, providing an alternative to sound is essential.

On our Website, as a complementary representation to the information in sound files or to the sound track on video, we have included written captions using the synchronized multimedia integration languate (SMIL). These SMIL files are always available but only appear at users' discretion. In this way, we ensure that the information carried in the sound files on the CAST Website is available to individuals who cannot hear them.

Moving video. Obviously, the visual information in moving video is no more accessible to individuals who are blind than are still images. Techniques for inserting descriptive language into digital versions of video have been developed, and we plan to add these elements to our Website as the technology becomes generally available.

Background knowledge. Often an individual's understanding of information depends on background knowledge. For example, understanding the meaning of the word "rock" depends on knowledge of the context of its use and alternate definitions. The word could be used equally correctly in a discussion about garage bands, geology, or something in motion ­ each to very different ends. Someone who makes an analogy to "bread crumb trails" assumes that the reader or listener is familiar with the story of Hansel and Gretel. Without such background knowledge, the analogy is more of a barrier than an aid. Information that assumes background knowledge but does not provide it will likely erect barriers for some users.

On the CAST Website, we have taken several initial steps to provide background knowledge. The site contains a tool for immediately getting an encyclopedia entry for any highlighted word (e.g., "limbic system"). Instead of a dictionary definition, the tool provides a general introduction intended to provide background knowledge for the visitor. In addition, many pages have hyperlinks, highlighted words that take the reader to more information about a topic. Many pages also have glossary items that have been specifically selected to provide background vocabulary and knowledge.

Barriers of Interaction and Navigation
A second type of barrier emerges from abilities (both physical and cognitive) a Website requires in order to navigate and interact within it. Challenges range from those that are motoric (e.g., requiring the visitor to use a keyboard or mouse) to those that are primarily strategic (e.g., requiring the visitor to decide the best plan for investigating the site). CAST's Website provides several kinds of support designed to address both of these challenges.
While there are no specific tools to aid physical action provided by the site, its digital construction lends itself to greater opportunities for action by individuals with physical disabilities, and we provide built-in linkages to a wide variety of assistive technologies (e.g., expanded keyboards, single switch access devices). With such devices, visitors can act upon the CAST Website in many different ways. There are command key equivalents for moving through a collection of pages (e.g. Learning to Read), and we look forward to implementing more in the near future.

In terms of cognitive and strategic challenges, we admit that the CAST Website is both extensive and complex. In other such sites, many individuals find barriers to successful navigation. Often, it is difficult for users to know where they are, to know what options are available, to distinguish between promising and unpromising paths, and to maintain attention and focus. When developing the CAST Website, we created a number of tools to support individuals who are navigating the site and to eliminate barriers to strategically navigating within it.

To begin with, we created a special navigation tool. This tool provides a taxonomical representation of the information in the site and always shows exactly where the individual is in a particular information domain. For example, individuals can see from the navigation tool that (a) they are in a section of the site called "brain foundations," (b) the section is a part of a larger section called "theoretical issues", and (c) the section may be part of an even larger section. The entire hierarchy is visible to the user. Moreover, all other choices at the same or higher level are clear.

An individual may navigate in a traditional fashion (e.g., by choosing a go-ahead button, or choosing options on the page) or may instead choose to navigate directly via the navigation tool. The latter choice allows an alternative representation of the site in terms of the information itself, and thus a very instructional alternative for navigation and exploration. Moreover, the tool is consistent across the site. Many Websites use navigation systems that change from one section to another and are not intuitive enough to provide easy cognitive exploration of the information space. In designing the CAST Website, we were careful to ensure that the Navigator Tool (http://www.cast.org/aboutsite/Navigator300.cfm) provided not only a consistent navigation mechanism but also spatial and hierarchical representations of the visitor's location at all times.

In addition, there are many alternative ways to navigate the site. There is a "bread crumb" tool that displays the last 20 stops the visitor has made in the site. This tool is specifically for individuals who like to explore adventitiously but can forget where they have been and how to return there. There are also many different navigation options directly on the page such as quick links to all of the main site areas, as well as previous and next links through pages of related information. Through these options, many different individuals may find a navigation method that is optimal for them.

Nevertheless, merely enabling efficient navigation of the site was not our ultimate goal. We had hoped that visitors would learn from the site. For this purpose, there are a number of ways that individuals can act on or through the site in order to learn more from it. Like many sites, the CAST site builds interactive experiences (all of them universally designed, of course). The Image Lab (http://www.cast.org/udl/ImageLab552.cfm ) is an example of one of these experiences. There, individuals can learn about making the information in images accessible to everyone by looking at models, getting supported practice, and sharing their results with others.

We also have provided additional tools for interactivity that are available everywhere on the site. A notepad tool (http://www.cast.org/aboutsite/Notepad303.cfm) allows visitors to annotate pages on the site with their own thoughts, observations, or criticisms. The annotations a visitor makes remain attached to the pages where the annotations were made, either for review on a return visit, or to leave as notes for others on a tour. Similarly, a feedback tool (http://www.cast.org/aboutsite/Feedback306.cfm) allows visitors to communicate in a contextually defined way with the content creators of the Website.
All of these tools were created with a simple goal in mind; to provide alternative ways to support the visitor in acting strategically within the CAST Website. The various tools were designed to reduce traditional barriers caused by limited ways of acting on and navigating in Web-based information. These tools will help to ensure that all individuals will know (a) where they are, (b) where they can go, and (c) what they can do on the Website.

Engagement Barriers
Not all visitors to the CAST site are motivated in the same way. They differ as individuals in what interests them, what draws or distracts their attention, what preferences they have for different kinds of learning, and what level of challenge or support they prefer. On the CAST Website we offer a variety of options to accommodate these differences. For example, the opening page to the Website is designed to provide alternative points of entry, to accommodate different user preferences. The front page is presented as a clickable floor plan, rather like a museum brochure or an illustrated trail map. For individuals who prefer to explore the site on their own terms, following their own interests as they arise, it is easy to "wander" around the Website in any order, looking for areas of interest.

At the opposite extreme are those individuals who come to the site with very specific questions or purposes. These individuals do not have to wander around the site because the opening page also has a search tool, where they can enter specific terms or phrases, and links to relevant pages will appear.

There are many other preferences between these two extremes. Some individuals may not have a specific question but also do not want to wander around completely on their own. One option for them is to take a guided tour, which is also available from the opening page. Guided tours provide structured introductions to the site materials. Each one hosted by a different individual, with different interests in mind. We think of these tours as analogous to visits to a National Park, where rangers may provide an excellent introduction to the environs. Several types of guided tours may cover the same terrain, with one emphasizing geology, another history, and another wildlife. In the same way, it is possible to take different guided tours of the same material on the CAST Website, each tour hosted by a different guide with a different interest. In fact, it is possible to make your own tour of the site, either to share with others, or for your own use on return visits.

There are several other intermediate ways to engage the CAST site. We find that returning visitors are very different than first-time visitors. For the former, there is a "find out what's new" point of entry, where visitors can go immediately to the material they have not yet seen (http://www.cast.org/about/index.cfm?i=295). Other individuals do not want to wander around the site but do want the highlights. For these visitors there is a "popular pages" directory on the home page (http://www.cast.org).

Often, for people with disabilities, the most important aspect of a site is whether it will accommodate their needs. For this reason, the opening home page also has an immediate link to a "how to customize this site" section (http://www.cast.org/aboutsite).
We hope that having all these options right on the home page sends the message that we recognize that people become engaged in very different ways. Providing alternative means of engagement is one way of acknowledging that fact.

Within the site there are many other ways that we have included alternatives for engagement. The guided tours, for example, allow different individuals to choose mentors or guides that have interests like their own. To meet individual differences in topic specific needs (e.g., those of a publisher as opposed to a teacher or a prospective donor), we provide highly specific pathways through our site content, as can be seen in the choices of guided tours (http://www.cast.org/tours/AvailableTours294.cfm).

Knowing that we cannot fully anticipate the entire spectrum of topic-specific needs that our visitors will bring, we provide mechanisms that allow our visitors to create and share their own interpretations of the site content (http://www.cast.org/aboutsite/Notepad303.cfm) and (http://www.cast.org/tours/MakeaTour308.cfm).

We also seek to increase engagement by allowing people to interact with material. The labs, only a limited number available at the moment, are one way we do this (http://www.cast.org/udl/MediaLabs351.cfm). In addition, most of the site allows people to interact with the material through tours, notes, and the like, but soon with each other through online forums.

CAST Website Evaluation
At the present time, our capacity for evaluation is at an early stage. Nonetheless, we have built in to the site several means for individuals to communicate their evaluations of what has been successful and what has not.

There is a "feedback tool" which allows the visitor to provide page-specific feedback to us at any time. An additional feature of this tool allows the visitor to ask us for our response to their feedback. At the same time, we are planning more formalized studies of how well we achieve the goals of our Website through upcoming focus groups and surveys.

Conclusion
The concept of Universal Design was built into the CAST Website from the outset. We worked from the initial design sessions to provide the flexibility in the site's infrastructure and interface that is needed for a UDL environment.

"The essence of UDL is flexibility and the inclusion of alternatives to adapt to the myriad variations in learner needs, styles, and preferencesOnly through a process of design that recognized the differentiated strengths and weaknesses of both students and media can we hope to create learning contexts and materials that are flexible enough to accommodate all learners."
--David Rose, CAST

To ensure flexibility of the content right from the beginning, we were careful to store all content in electronic format, within a relational database that allows the transformation of content at the point of request (rather than using hard-coded HTML files). We developed a flexible, extensible, and customizable user interface that allows visitors to select the tools they want at the point of need, rather than cluttering the interface (http://www.cast.org/aboutsite/). We were careful to allow visitors to customize, save, and retrieve their interface settings (http://www.cast.org/mycast). We also designed the interface to allow for easy expansion of functionality in the future.

Knowing that visitors to the site can contribute to the value of information in the Website, we worked to encourage interaction and communication. The Guided Tours (URL) and Notepad (URL) features encourage re-evaluation and reformulation of the information on the site. The Guided Tours allow different visitors to exchange information, knowledge, and skills with each other.

Obviously, the CAST site is not a perfect example of Universal Design for Learning -- far from it. Universal Design is a process, not an outcome. Our Website is merely a first step towards the kinds of designs that we hope to make. We share it with you at this point to make the learning explicit. To that end, we look forward to learning from you.