Research-based web design and usability guidelines

Draft

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This page contains excerpts of the Research-Based Web Design & Usability Guidelines at usability.gov

Introduction

“The Research-Based Web Design & Usability Guidelines (Guidelines) were developed by the U.S. Department of Health and Human Services (HHS), in partnership with the U.S. General Services Administration. This new edition of the Guidelines updates the original set of 187 guidelines, and adds 22 new ones. Many of the guidelines were edited, and numerous new references have been added. There are now 209 guidelines. [..] The primary audiences for the Guidelines are Web site managers, designers, and others involved in the creation or maintenance of Web sites. A secondary audience is researchers who investigate Web design issues.” (p. XV)

Each guideline is rankend in importance and scientific evidence. One foreword is written by Ben Shneiderman and we suspect that he played an important role in the design of this document. Authors were supported by a large panel of respected researchers and practitioners.

“This newest set of guidelines from the prestigious team assembled by the Department of Health and Human Services makes important contributions that will benefit practitioners and researchers. They have done the meticulous job of scouring the research literature to find support for design guidelines, thereby clarifying the message, resolving inconsistencies, and providing sources for further reading. Researchers will also benefit by this impressive compilation that will help them understand the current state of the art and see what problems are unresolved. Another impact will be on epistemologists and philosophers of science who argue about the relevance of research to practice. It is hard to recall a project that has generated as clear a demonstration of the payoff of research for practice.” (Ben Shneiderman, Introduction, p IV)

The purpose of this page is to present some of these guidelines in a single page for teaching purposes. (I hate dealing with 20MB PDF file for display in a classroom ....)

Important guidelines

The guidelines we present below are chosen (a) by their importance and (b) for various other reasons :)

Look at the original if you want to real thing ! Also, its the authors promised a database-base solution at some point. Contents below are (unless otherwise indicated) just copy/paste.

Design Process and Evaluation

There are several usability-related issues,methods, and procedures that require careful consideration when designing and developing Web sites. The most important of these are presented in this chapter, including ’up-front’ issues such as setting clear and concise goals for a Web site, determining a correct and exhaustive set of user requirements, ensuring that the Web site meets user’s expectations, setting usability goals, and providing useful content.

To ensure the best possible outcome, designers should consider a full range of user-interface issues, and work to create a Web site that enables the best possible human performance. The current research suggests that the best way to begin the construction of a Web site is to have many different people propose design solutions (i.e., parallel design), and then to follow up using an iterative design approach. This requires conducting the appropriate usability tests and using the findings to make changes to the Web site.

- 1:1 Provide Useful Content

Guideline: Provide content that is engaging, relevant, and appropriate to the audience.

Comments: Content is the information provided on a Web site. Do not waste resources providing easy access and good usability to the wrong content. One study found that content is the most critical element of a Web site. Other studies have reported that content is more important than navigation, visual design, functionality, and interactivity.

- 1:2 Establish User Requirements

Guideline: Use all available resources to better understand users’ requirements.

Comments: The greater the number of exchanges of information with potential users, the better the developers’ understanding of the users’ requirements. The more information that can be exchanged between developers and users, the higher the probability of having a successful Web site. These could include customer support lines, customer surveys and interviews, bulletin boards, sales people, user groups, trade show experiences, focus groups, etc. Successful projects require at least four (and average five) different sources of information. Do not rely too heavily on user intermediaries. [...]

- 1:3 Understand and Meet User’s Expectations

Guideline: Ensure that the Web site format meets user expectations, especially related to navigation, content, and organization.

Comments: One study found that users define 'usability' as their perception of how consistent, efficient, productive, organized, easy to use, intuitive, and straightforward it is to accomplish tasks within a system. [...]

- 1:4 Involve Users in Establishing User Requirements

Guideline: Involve users to improve the completeness and accuracy of user requirements.

Comments: One of the basic principles of user-centered design is the early and continual focus on users. For this reason, user involvement has become a widely accepted principle in the development of usable systems. Involving users has the most value when trying to improve the completeness and accuracy of user requirements. [...] Users are most valuable in helping designers know what a system should do, but not in helping designers determine how best to have the system do it

Optimizing the User Experience

Web sites should be designed to facilitate and encourage efficient and effective human-computer interactions. Designers should make every attempt to reduce the user’s workload by taking advantage of the computer’s capabilities. Users will make the best use of Web sites when information is displayed in a directly usable format and content organization is highly intuitive. Users also benefit from task sequences that are consistent with how they typically do their work, that do not require them to remember information for more than a few seconds, that have terminology that is readily understandable, and that do not overload them with information.

Users should not be required to wait for more than a few seconds for a page to load, and while waiting, users should be supplied with appropriate feedback. Users should be easily able to print information. Designers should never ‘push’ unsolicited windows or graphics to users.

- 2:1 Do Not Display Unsolicited Windows or Graphics

Guideline: Do not have unsolicited windows or graphics ‘pop-up’ to users.

Comments: Users have commented that unsolicited windows or graphics that ‘pop up’ are annoying and distracting when they are focusing on completing their original activity.

- 2:2 Increase Web Site Credibility

Guideline: Optimize the credibility of information-oriented Web sites.

Comments: Based on the results of two large surveys, the most important Web site-related actions that organizations can do to help ensure high Web site credibility are to:

• Provide a useful set of frequently asked questions (FAQ) and answers;
• Ensure the Web site is arranged in a logical way;
• Provide articles containing citations and references;
• Show author’s credentials;
• Ensure the site looks professionally designed;
• Provide an archive of past content (where appropriate);
• Ensure the site is as up-to-date as possible;
• Provide links to outside sources and materials; and
• Ensure the site is frequently linked to by other credible sites.

- 2:3 Standardize Task Sequences

Guideline: Allow users to perform tasks in the same sequence and manner across similar conditions.

Comments: Users learn certain sequences of behaviors and perform best when they can be reliably repeated. For example, users become accustomed to looking in either the left or right panels for additional information. Also, users become familiar with the steps in a search or checkout process.

- 2:4 Reduce the User’s Workload

Guideline: Allocate functions to take advantage of the inherent respective strengths of computers and users.

Comments: Let the computer perform as many tasks as possible, so that users can concentrate on performing tasks that actually require human processing and input. Ensure that the activities performed by the human and the computer take full advantage of the strengths of each. For example, calculating body mass indexes, remembering user IDs, and mortgage payments are best performed by computers.

- 2:5 Design for Working Memory Limitations

Comments: Users can remember relatively few items of information for a relatively short period of time. This ’working memory’ capacity tends to lessen even more as people become older. One study compared the working memory performance of age groups 23-44 years and 61-68 years. The younger group performed reliably better than the older group.

When users must remember information on one Web page for use on another page or another location on the same page, they can only remember about three or four items for a few seconds. If users must make comparisons, it is best to have the items being compared side-by-side so that users do not have to remember information—even for a short period of time.

- 2:8 Display Information in a Directly Usable Format

Guideline: Display data and information in a format that does not require conversion by the user.

Comments: Present information to users in the most useful and usable format possible. Do not require users to convert or summarize information in order for it to be immediately useful. It is best to display data in a manner that is consistent with the standards and conventions most familiar to users.

- 2:9 Format Information for Reading and Printing

Guideline: Prepare information with the expectation that it will either be read online or printed.

Comments: Documents should be prepared that are consistent with whether users can be expected to read the document online or printed. One study found that the major reason participants gave for deciding to read a document from print or to read it online was the size of the document. Long documents (over five pages) were printed, and short documents were read online. In addition, users preferred to print information that was related to research, presentations, or supporting a point. They favored reading it online if for entertainment. Users generally favored reading documents online because they could do it from anywhere at anytime with 24/7 access. Users were inclined to print (a) if the online document required too much scrolling, (b) if they needed to refer to the document at a later time, or (c) the complexity of the document required them to highlight and write comments.

[Like: Do not use PDF for a guide such as this one, couldn't resist - 22:02, 15 March 2011 (CET)]

- 2:10 Provide Feedback when Users Must Wait

Guideline: Provide users with appropriate feedback while they are waiting.

Comments: If processing will take less than 10 seconds, use an hourglass to indicate status. If processing will take up to sixty seconds or longer, use a process indicator that shows progress toward completion, [etc....]

- 2:13 Do Not Require Users to Multitask While Reading

Guideline: If reading speed is important, do not require users to perform other tasks while reading from the monitor.

Comments: Generally, users can read from a monitor as fast as they can from paper, unless they are required to perform other tasks that require human ’working memory’ resources while reading. For example, do not require users to look at the information on one page and remember it while reading the information on a second page. This can reliably slow their reading performance.

- 2:16 Provide Assistance to Users

Guideline: Provide assistance for users who need additional help with the Web site.

Comments: Users sometimes require special assistance. This is particularly important if the site was designed for inexperienced users or has many first time users

Acessibility

See Acessibility

Hardware and Software

Just as designers consider their users’ needs for specific information, they must also consider any constraints imposed on them by their users’ hardware, software, and speed of connection to the Internet. Today, a single operating system (Microsoft’s XP) dominates personal computer market.

Similarly, only two Web site browsers are favored by the vast majority of users. More than ninety percent of users have their monitors set to 1024x768, 800x600 or 1280x1024 pixel resolution. And while most users at work have high-speed Internet access, many home users still connect using dial-up.

- 4:1 Design for Common Browsers

Guideline: Design, develop and test for the most common browsers.

Comments: Designers should attempt to accommodate ninety-five percent of all users. Ensure that all testing of a Web site is done using the most popular browsers.

- 4:2 Account for Browser Differences

Guideline: Do not assume that all users will have the same browser features, and will have set the same defaults.

Comments: Users with visual impairments tend to select larger fonts, and some users may turn off backgrounds, use fewer colors, or overrides font. The designer should find out what settings most users are using, and specify on the Web site exactly what assumptions were made about the browser settings.

- 4:4 Design for User’s Typical Connection Speed

Guideline: Design for the connection speed of most users.

Comments: [...] Designers should consult one of the several sources that maintain current figures.

- 4:5 Design for Commonly Used Screen Resolutions

Guideline: Design for monitors with the screen resolution set at 1024x768 pixels.

Comments: Designers should attempt to accommodate ninety-five percent of all users. As of June 2006, 56% of users have their screen resolution set at 1024x768.

[I can't agree with this. Cellphones have lower resolution, and normal workstations of laptops got more. Therefore go for fluid designs - Daniel K. Schneider 22:02, 15 March 2011 (CET)]

The Homepage

The homepage is different from all other Web site pages. A well-constructed homepage will project a good first impression to all who visit the site.

It is important to ensure that the homepage has all of the features expected of a homepage and looks like a homepage to users. A homepage should clearly communicate the site's purpose, and show all major options available on the Web site. Generally, the majority of the homepage should be visible ’above the fold,’ and should contain a limited amount of prose text. Designers should provide easy access to the homepage from every page in the site.

- 5:1 Enable Access to the Homepage

Guideline: Enable users to access the homepage from any other page on the Web site.

Comments: Many users return to the homepage to begin a new task or to start a task over again. Create an easy and obvious way for users to quickly return to the homepage of the Web site from any point in the site. Many sites place the organization’s logo on the top of every page and link it to the homepage. While many users expect that a logo will be clickable, many other users will not realize that it is a link to the homepage. Therefore, include a link labeled ‘Home’ near the top of the page to help those users.

- 5:2 Show All Major Options on the Homepage

Guideline: Present all major options on the homepage.

Comments: Users should not be required to click down to the second or third level to discover the full breadth of options on a Web site. Be selective about what is placed on the homepage, and make sure the options and links presented there are the most important ones on the site.

- 5:3 Create a Positive First Impression of Your Site

Guideline: Treat your homepage as the key to conveying the quality of your site.

Comments: In terms of conveying quality, the homepage is probably the most important page on a Web site. One study found that when asked to find high quality Web sites, about half of the time participants looked only at the homepage. You will not get a second chance to make a good first impression on a user.

- 5:4 Communicate the Web Site’s Value and Purpose

Guideline: Clearly and prominently communicate the purpose and value of the Web site on the homepage.

Comments: Most people browsing or searching the Web will spend very little time on each site. Emphasize what the site offers that is of value to users, and how the site differs from key competitors. Many users waste time because they misunderstand the purpose of a Web site. In one study, most users expected that a site would show the results of research projects, not merely descriptions of project methodology.

In some cases the purpose of a Web site is easily inferred. In other cases, it may need to be explicitly stated through the use of brief text or a tagline. Do not expect users to read a lot of text or to click into the Site to determine a Site’s purpose. Indicating what the Site offers that is of value to users, and how the Site differs from key competitors is important because most people will spend little time on each Site.

- 5:5 Limit Prose Text on the Homepage

Guideline: Limit the amount of prose text on the homepage.

Comments: The first action of most users is to scan the homepage for link titles and major headings. Requiring users to read large amounts of prose text can slow them considerably, or they may avoid reading it altogether.

- 5:6 Ensure the Homepage Looks like a Homepage

Guideline: Ensure that the homepage has the necessary characteristics to be easily perceived as a homepage.

Comments: It is important that pages ’lower’ in a site are not confused with the homepage. Users have come to expect that certain actions are possible from the homepage. These actions include, among others, finding important links, accessing a site map or index, and conducting a search.

- 5:7 Limit Homepage Length

Guideline: Limit the homepage to one screenful of information, if at all possible.

Comments: Any element on the homepage that must immediately attract the attention of users should be placed ’above the fold.’ Information that cannot be seen in the first screenful may be missed altogether—this can negatively impact the effectiveness of the Web site. If users conclude that what they see on the visible portion of the page is not of interest, they may not bother scrolling to see the rest of the page.

Some users take a long time to scroll down ’below the fold,’ indicating a reluctance to move from the first screenful to subsequent information. Older users and novices are more likely to miss information that is placed below the fold.

[This is true for most web sites. Users are used to scroll down on blogs and other text-based sites - 22:29, 15 March 2011 (CET)]

- 5:8 Announce Changes to a Web Site

Guideline: Announce major changes to a Web site on the homepage—do not surprise users.

Comments: Introducing users to a redesigned Web site can require some preparation of expectations. Users may not know what to do when they are suddenly confronted with a new look or navigation structure.

- Page Layout

All Web pages should be structured for ease of comprehension. This includes putting items on the page in an order that reflects their relative importance. Designers should place important items consistently, usually toward the top and center of the page. All items should be appropriately aligned on the pages. It is usually a good idea to ensure that the pages show a moderate amount of white space—too much can require considerable scrolling, while too little may provide a display that looks too ‘busy.’ It is also important to ensure that page layout does not falsely convey the top or bottom of the page, such that users stop scrolling prematurely.

When a Web page contains prose text, choose appropriate line lengths. Longer line lengths usually will elicit faster reading speed, but users tend to prefer shorter line lengths. There are also important decisions that need to be made regarding page length. Pages should be long enough to adequately convey the information, but not so long that excessive scrolling becomes a problem. If page content or length dictates scrolling, but the page's table of contents needs to be accessible, then it is usually a good idea to use frames to keep the table of contents readily accessible and visible in the left panel.

- 6:1 Avoid Cluttered Displays

Guideline: Create pages that are not considered cluttered by users.

Comments: Clutter is when excess items on a page lead to a degradation of performance when trying to find certain information. On an uncluttered display, all important search targets are highly salient, i.e., clearly available. One study found that test participants tended to agree on which displays were least cluttered and those that were most cluttered.

- 6:2 Place Important Items Consistently

Guideline: Put important, clickable items in the same locations, and closer to the top of the page, where their location can be better estimated.

Comments: Users will try to anticipate where items will appear on their screen. They will start ’searching’ a page before the layout appears on their screen. When screen items remain constant, users learn their location on a page, and use this knowledge to improve task performance. Experienced users will begin moving their mouse to the area of the target before the eye detects the item. Users can anticipate the location of items near the top much better than those farther down the page.

- 6:3 Place Important Items at Top Center

Guideline: Put the most important items at the top center of the Web page to facilitate users’ finding the information.

Comments: Users generally look at the top center of a page first, then look left, then right, and finally begin systematically moving down the total Web page. All critical content and navigation options should be toward the top of the page. Particularly on navigation pages, most major choices should be visible with no, or a minimum of, scrolling.

- 6:4 Structure for Easy Comparison

Guideline: Structure pages so that items can be easily compared when users must analyze those items to discern similarities, differences, trends, and relationships.

Comments: Users should be able to compare two or more items without having to remember one while going to another page or another place on the same page to view a different item.

- 6:5 Establish Level of Importance

Guideline: Establish a high-to-low level of importance for information and infuse this approach throughout each page on the Web site.

Comments: The page layout should help users find and use the most important information. Important information should appear higher on the page so users can locate it quickly. The least used information should appear toward the bottom of the page. Information should be presented in the order that is most useful to users. People prefer hierarchies, and tend to focus their attention on one level of the hierarchy at a time. This enables them to adopt a more systematic strategy when scanning a page, which results in fewer revisits.

- 6:6 Optimize Display Density

Guideline: To facilitate finding target information on a page, create pages that are not too crowded with items of information.

Comments: Density can be defined as the number of items per degree of visual angle within a visually distinct group. This density either can be crowded with many items, or sparse with few items. One study found that locating a target in a crowded area took longer than when the target was in a sparse area. Also, participants searched and found items in the sparse areas faster than those in the crowded areas. Participants used fewer fixations per word in the crowded areas, but their fixations were much longer when viewing items in the crowded areas. Finally, participants tended to visit sparse areas before dense groups. To summarize, targets in sparse areas of the display (versus crowded areas) tended to be searched earlier and found faster.

- 6:7 Align Items on a Page

Guideline: Visually align page elements, either vertically or horizontally.

Comments: Users prefer consistent alignments for items such as text blocks, rows, columns, checkboxes, radio buttons, data entry fields, etc. Use consistent alignments across all Web pages.

- 6:8 Use Fluid Layouts

Guideline: Use a fluid layout that automatically adjusts the page size to monitor resolution settings that are 1024x768 pixels or higher.

Comments: When web page layouts are fixed either to the left or centered, much of the available screen space is not used. It is best to take advantage of as much of the screen space as possible because this will help move more information above the fold. There has been no degradation in user performance when using the non-fluid layouts. However, most users prefer the fluid layout. One 2003 study reported a compliance rate for this guideline of twenty-eight percent, and a 2001 study found that only twenty-three percent of top Web sites used a fluid layout. Keep in mind that large monitors and higher pixel resolutions allow viewing of more than one window at a time.

- 6:10 Set Appropriate Page Lengths

Guideline: Make page-length decisions that support the primary use of the Web page.

Comments: In general, use shorter pages for homepages and navigation pages, and pages that need to be quickly browsed and/or read online. Use longer pages to (1) facilitate uninterrupted reading, especially on content pages; (2) match the structure of a paper counterpart; (3) simplify page maintenance (fewer Web page files to maintain); and, (4) make pages more convenient to download and print.

Navigation

Navigation refers to the method used to find information within a Web site. A navigation page is used primarily to help users locate and link to destination pages. A Web site’s navigation scheme and features should allow users to find and access information effectively and efficiently. When possible, this means designers should keep navigation-only pages short. Designers should include site maps, and provide effective feedback on the user’s location within the site.

To facilitate navigation, designers should differentiate and group navigation elements and use appropriate menu types. It is also important to use descriptive tab labels, provide a clickable list of page contents on long pages, and add ‘glosses’ where they will help users select the correct link. In well-designed sites, users do not get trapped in dead-end pages.

- 7:1 Provide Navigational Options

Guideline: Do not create or direct users into pages that have no navigational options.

Comments: Many Web pages contain links that open new browser windows. When these browser windows open, the Back button is disabled (in essence, the new browser window knows nothing of the user’s past navigation, and thus is disabled). If the new window opens full-screen, users may not realize that they have been redirected to another window, and may become frustrated because they cannot press Back to return to the previous page. If such links are incorporated into a Web site, the newly-opened window should contain a prominent action control that will close the window and return the user to the original browser window.

In addition, designers should not create Web pages that disable the browser’s Back button. Disabling the Back button can result in confusion and frustration for users, and drastically inhibits their navigation.

- 7:2 Differentiate and Group Navigation Elements

Guideline: Clearly differentiate navigation elements from one another, but group and place them in a consistent and easy to find place on each page.

Comments: Create a common, Web site-wide navigational scheme to help users learn and understand the structure of your Web site. Use the same navigation scheme on all pages by consistently locating tabs, headings, lists, search, site map, etc. Locate critical navigation elements in places that will suggest clickability (e.g., lists of words in the left or right panels are generally assumed to be links).

Make navigational elements different enough from one another so that users will be able to understand the difference in their meaning and destination. Grouping reduces the amount of time that users need to locate and identify navigation elements.

Do not make users infer the label by studying a few items in the group. Finally, make it easy for users to move from label to label (link to link) with a single eye movement. This best can be done by positioning relevant options close together and to using vertical lists.

- 7:3 Use a Clickable ‘List of Contents’ on Long Pages

Guideline: On long pages, provide a ’list of contents’ with links that take users to the corresponding content farther down the page.

Comments: For long pages with several distinct sections that are not visible from the first screenful, add a short, clickable list of the sections (sometimes called ’anchor’ or ’within-page’ links) at the top of the page. ’Anchor links’ can serve two purposes: they provide an outline of the page so users can quickly determine if it contains the desired information, and they allow users to quickly navigate to specific information.

Since ’anchor links’ enable a direct link to content below the first screenful, they are also useful for getting users to specific information quickly when they arrive from a completely different page.

- 7:4 Provide Feedback on Users’ Location

Guideline: Provide feedback to let users know where they are in the Web site.

Comments: Feedback provides users with the information they need to understand where they are within the Web site, and for proceeding to the next activity. Examples of feedback include providing path and hierarchy information (i.e., ’breadcrumbs’), matching link text to the destination page’s heading, and creating URLs that relate to the user’s location on the site. Other forms of feedback include changing the color of a link that has been clicked (suggesting that destination has been visited), and using other visual cues to indicate the active portion of the screen.

- 7:5 Place Primary Navigation Menus in the Left Panel

Guideline: Place the primary navigation menus in the left panel, and the secondary and tertiary menus together.

Comments: One study found that navigation times were faster when the primary menu was located in the left panel. Also, navigation performance was best when the secondary and tertiary menus were placed together. Placing a navigation menu in the right panel was supported as a viable design option by both performance and preference measures. Users preferred having the primary menu in the left panel, and grouping secondary and tertiary menus together, or grouping all three menu levels together. The best performance and preference was achieved when all three menus were placed in the left panel (placing them all in the right panel achieved close to the same performance level).

- 7:6 Use Descriptive Tab Labels

Guideline: Ensure that tab labels are clearly descriptive of their function or destination.

Comments: Users like tabs when they have labels that are descriptive enough to allow error-free selections. When tab labels cannot be made clear because of the lack of space, do not use tabs.

- 7:8 Keep Navigation-Only Pages Short

Guideline: Do not require users to scroll purely navigational pages.

Comments: Ideally, navigation-only pages should contain no more than one screenful of information. Users should not need to scroll the page, even a small distance. One study showed that users considered the bottom of one screenful as the end of a page, and they did not scroll further to find additional navigational options.

- 7:12 Breadcrumb Navigation

Guideline: Do not expect users to use breadcrumbs effectively.

Comments: One study reported no difference in task completion times and total pages visited between groups that had breadcrumbs and those that did not. Participants could have used breadcrumbs thirty-two percent of the time, but only did so six percent of the time. It is probably not worth the effort to include breadcrumbs unless you can show that your Web site’s users use them frequently, either to navigate the site, or to understand the site’s hierarchy. One study found that test participants who received instruction on the use of breadcrumbs completed tasks much faster than those who did not. This time savings could result in increased productivity for users that search Web sites on a daily basis.

[Ha tell Nielen ! - 22:29, 15 March 2011 (CET)]

Scrolling and Paging

Designers must decide, early in the design process, whether to create long pages that require extensive scrolling or shorter pages that will require users to move frequently from page to page (an activity referred to as paging). This decision will be based on considerations of the primary users and the type of tasks being performed. For example, older users tend to scroll more slowly than younger users; therefore, long scrolling pages may slow them down considerably. As another example, some tasks that require users to remember where information is located on a page may benefit from paging, while many reading tasks benefit from scrolling.

Generally, designers should ensure that users can move from page to page as efficiently as possible. If designers are unable to decide between paging and scrolling, it is usually better to provide several shorter pages rather than one or two longer pages. The findings of usability testing should help confirm or negate that decision.

When scrolling is used, a Web site should be designed to allow the fastest possible scrolling. Users only should have to scroll through a few screenfuls, and not lengthy pages. Designers should never require users to scroll horizontally.

- 8:1 Eliminate Horizontal Scrolling

Guideline: Use an appropriate page layout to eliminate the need for users to scroll horizontally.

Comments: Horizontal scrolling is a slow and tedious way to view an entire screen. Common page layouts including fluid and left-justified may require some users to scroll horizontally if their monitor resolution or size is smaller than that used by designers.

- 8:3 Use Scrolling Pages For Reading Comprehension

Guideline: Use longer, scrolling pages when users are reading for comprehension.

Comments: Make the trade-off between paging and scrolling by taking into consideration that retrieving new linked pages introduces a delay that can interrupt users’ thought processes. Scrolling allows readers to advance in the text without losing the context of the message as may occur when they are required to follow links. [...]

Headings, Titles, and Labels

Most users spend a considerable amount of time scanning rather than reading information on Web sites. Well-designed headings help to facilitate both scanning and reading written material. Designers should strive to use unique and descriptive headings, and to use as many headings as necessary to enable users to find what they are looking for—it is usually better to use more rather than fewer headings. Headings should be used in their appropriate HTML order, and it is generally a good idea not to skip heading levels.

Designers should ensure that each page has a unique and descriptive page title. When tables are used, designers should make sure that descriptive row and column headings are included that enable users to clearly understand the information in the table. It is occasionally important to highlight certain critical information.

- 9:1 Use Clear Category Labels

Guideline: Ensure that category labels, including links, clearly reflect the information and items contained within the category.

Comments: Category titles must be understood by typical users. Users will likely have difficulty understanding vague, generalized link labels, but will find specific, detailed links, and descriptors easier to use.

- 9:2 Provide Descriptive Page Titles

Guideline: Put a descriptive, unique, concise, and meaningfully different title on each Web page.

Comments: Title refers to the text that is in the browser title bar (this is the bar found at the very top of the browser screen). Titles are used by search engines to identify pages. If two or more pages have the same title, they cannot be differentiated by users or the Favorites capability of the browser. If users bookmark a page, they should not have to edit the title to meet the characteristics mentioned above.

Remember that some search engines only list the titles in their search results page. Using concise and meaningful titles on all pages can help orient users as they browse a page or scan hot lists and history lists for particular URLs. They can also help others as they compile links to your pages.

To avoid confusing users, make the title that appears in the heading of the browser consistent with the title in the content area of the pages.

- 9:3 Use Descriptive Headings Liberally

Guideline: Use descriptive headings liberally throughout a Web site.

Comments: Well-written headings are an important tool for helping users scan quickly. Headings should conceptually relate to the information or functions that follow them. Headings should provide strong cues that orient users and inform them about page organization and structure. Headings also help classify information on a page. Each heading should be helpful in finding the desired target.

The ability to scan quickly is particularly important for older adults because they tend to stop scanning and start reading more frequently. If headings are not descriptive or plentiful enough, the user may start reading in places that do not offer the information they are seeking, thereby slowing them down unnecessarily.

- 9:4 Use Unique and Descriptive Headings

Guideline: Use headings that are unique from one another and conceptually related to the content they describe.

Comments: Using poor headings (mismatches between what users were expecting and what they find) is a common problem with Web sites. Ensure that headings are descriptive and relate to the content they introduce.

If headings are too similar to one another, users may have to hesitate and re-read to decipher the difference. Identifying the best headings may require extensive usability testing and other methods.

- 9:5 Highlight Critical Data

Guideline: Visually distinguish (i.e., highlight) important page items that require user attention, particularly when those items are displayed infrequently.

Comments: Items to highlight might include recently changed data, data exceeding acceptable limits, or data failing to meet some other defined criteria. Highlight is used here in its general sense, meaning to emphasize or make prominent. Highlighting is most effective when used sparingly, i.e., highlighting just a few items on a page that is otherwise relatively uniform in appearance.

- 9:7 Use Headings in the Appropriate HTML Order

Guideline: Use headings in the appropriate HTML order.

Comments: Using the appropriate HTML heading order helps users get a sense of the hierarchy of information on the page. The appropriate use of H1-H3 heading tags also allows users of assistive technologies to understand the hierarchy of information.

Links

Linking means that users will select and click on a hypertext link on a starting page (usually the homepage), which then causes a new page to load. Users continue toward their goal by finding and clicking on subsequent links.

To ensure that links are effectively used, designers should use meaningful link labels (making sure that link names are consistent with their targets), provide consistent clickability cues (avoiding misleading cues), and designate when links have been clicked.

Whenever possible, designers should use text for links rather than graphics. Text links usually provide much better information about the target than do graphics.

Links

• Research-Based Web Design & Usability Guidelines homepage at usability.gov