What Does “Predictable” Mean in WCAG? Comprehensive Guide to Achievement Criteria and Methods

*This article is an English translation of a Japanese article.

Introduction

JIS X 8341-3:2016, the Japanese web accessibility standard, outlines various achievement criteria to ensure that websites are easy to navigate and use for all users. One of the key criteria is “predictability,” which focuses on making website behavior and navigation understandable to users. This guide will explain the achievement criteria related to “predictability” and provide specific methods to ensure your website meets these standards.

Overview of the “Predictable” Achievement Criteria

The “predictable” achievement criteria aim to ensure that a website’s behavior and structure are consistent, making it easier for users to anticipate what will happen next. This is especially important for users with cognitive disabilities, visual impairments, or the elderly, who may have difficulty navigating websites with unexpected changes or inconsistent layouts. Key aspects include:

• Consistent navigation: Elements like menus and buttons are consistently placed across all pages.
• Avoiding unexpected changes: Pages should not reload or change unexpectedly based on user actions.
• Clear feedback: When users take actions, they receive clear feedback, so they understand what has happened and what to do next.

These principles help users navigate websites without confusion, allowing them to accomplish their tasks smoothly.

Specific Requirements of the Achievement Criteria

To meet the “predictable” achievement criteria, several specific requirements must be addressed:

1. Consistent Navigation Placement
   Navigation menus and key elements should be placed in the same location on every page. This consistency allows users to find and use these elements without having to re-learn where things are on each page.

2. Avoid Sudden Changes When Inputting Information
   When users interact with forms or dropdown menus, the page should not suddenly navigate away or update without their explicit action. For example, rather than triggering a page change when a user selects an option, provide a “Submit” button so that they can control the timing of the next step.

3. Clear Labels for Links and Buttons
   Buttons and links should clearly describe what action will occur when clicked. Instead of using vague text like “Click here,” use specific text such as “Go to the details page” or “Proceed to the application form,” so users know exactly what to expect.

4. Control Over New Windows or Tabs
   If a link opens a new window or tab, this action should be clearly indicated. For example, add text like “Opens in a new tab” to inform users and prevent confusion.

5. Avoid Automatic Page Refreshes
   Automatically refreshing a page can disrupt users, especially if they are in the middle of reading or interacting with the content. If auto-refresh is necessary, inform users ahead of time so they are not caught off-guard.

Practical Measures for Website Operators

To ensure compliance with the “predictable” achievement criteria, website operators and developers should take the following measures:

• Adopt a consistent design: Ensure that the navigation, buttons, and other interactive elements are positioned in the same location on every page, and use a consistent design throughout the website.
• Provide clear feedback to user actions: Show visual indicators such as loading animations when a button is clicked, or display confirmation messages when a form is submitted. This helps users understand the result of their actions.
• Conduct user testing: Perform user testing with groups that include individuals with disabilities, such as those with visual impairments or cognitive disabilities. This helps identify any predictability issues, allowing for targeted improvements.
• Review link and button labels: Ensure that all links and buttons have clear, descriptive labels that accurately reflect the action they perform. Update any vague labels to provide more precise information.

Importance and Benefits of Predictability

Implementing a predictable design reduces user confusion and creates an environment where they can confidently navigate the site. This is particularly beneficial for elderly users and those with cognitive disabilities, as it improves their overall web experience. Moreover, predictability enhances user engagement, which can positively impact conversion rates and overall user satisfaction.

Conclusion

The “predictable” achievement criteria in JIS X 8341-3:2016 are essential for ensuring that users can anticipate the results of their interactions on a website. Consistent navigation, preventing unexpected changes, and providing clear feedback are key practices for achieving a predictable user experience. Following these guidelines helps create a website that is accessible, user-friendly, and inclusive for all users.

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