Morten Tollefsen, Cathy Kalvenes, Miriam Nes Begnum
The recent Norwegian Discrimination and Accessibility Act will place much greater demands on Universal design of Web technology. Web sites should be accessible and usable for everyone, also all groups of disabled users.
The Web Content Accessibility guidelines (WCAG 2.0) to some extent ensure usability. However usability obviously requires that disabled users have specific knowledge. What is "perceivable" and "operable", according to the WCAG guidelines, will be determined by the level of knowledge / experience the user has. A definable and measurable level of user competence is therefore important for testing and developing accessible and usable Web sites, and will be meaningful in all Research and Development projects focusing on Web technology.
The main goal of this project is to define demands for user qualifications to utilize WCAG 2.0 Web sites and to use the definition to develop a framework to teach and test required user skills. The two user groups in focus are: blind and severely visually impaired users, and users with cognitive disabilities.
This document is the first version of user demands for persons using a screen reader.
In principle sighted and visually impaired persons should have comparable theoretical and identical practical knowledge. Techniques may vary, but visually impaired and sighted users should be able to perform the same tasks given an accessible website. When trying to define demands for user competence, it is therefore advantageous to use a standardized certification scheme.
The International Computer Driving License (ICDL) is built on 7 modules. One of these modules (number 7) is "Web browsing and communication". The skills outlined in module 7 should enable a user to manage the web efficiently. Module 7 also includes email which is not a part of this user demand specification.
The skills and theoretical knowledge specified in ICDL module 7 are used as a basis for demands for qualifications for visually impaired persons. In addition, to be able to work quickly and efficiently on a website, a screen reader user needs to master techniques and functionality specific to the screen reader. This knowledge is described below.
Screen readers use different terminology. Virtual mode is an example. Below virtual mode is used to describe the adapted presentation typically created by screen readers to simplify the layout of web pages. Virtual cursor is the insertion point used in virtual mode. Virtual cursor/mode is the terminology in the Jaws screen reader. Browser mode is used in Window-Eyes.
Visually impaired users use the Web interface in combination with assistive technologies such as a screen reader (synthetic speech and/or Braille display). Reading and moving through the Web interface requires both knowledge of the browser user interface, and how the screen reader works. A screen reader typically uses a virtual cursor, reading the Web page content from top to bottom, in a similar way to reading a word processing document. This page conversion is desirable when the user reads a few Braille characters at a time and/or hears a single word at a time, and is quite different from the visual presentation. The visually impaired user, and the sighted teacher, should be aware of the difference.
Most screen readers have better support for synthetic speech than Braille. Research shows that one works about 80 % faster using synthetic speech support than using only Braille - even when a highly skilled Braille user. In most screen readers accurate perception of synthetic speech is required for a blind user to be able to obtain the necessary information from the web page. Examples of this are:
Braille users should therefore also be able to use and understand synthetic speech.
The user needs to know the following most basic speech commands:
Persons with a severe hearing disability are perhaps not able to use synthetic speech. Deaf-dump and hearing impaired should know how to get information through screen readers, although not being able to hear the synthetic speech.
Because synthetic speech and Braille displays can read/show a very limited amount of text at a time, it is important for the user to know the basic cursor movement keys such as:
It is also important for the user to be able to select and copy text. Often selecting text is similar to moving the cursor, with an additional modifier key (e. g. shift). The users should know how to:
A blind user must understand how links (visually displayed by color formatting, underlining, etc.) are presented by the screen reader. Often links are displayed on their own line when reading with the virtual cursor. The links are typically announced as "link", "visited link", "link graphic" and so on (some screen readers show this in Braille as well, others don't).
On a web page which is not familiar, the user may move through the links by pressing Tab for the next link, or Shift+Tab for the previous link as these commands cycle through all links. This is very time consuming on a large page. The user should therefore also be able to select links using the link list functionality found in most screen readers and/or browsers. Selecting links using initial letter(s) is the most important link selection feature. Selecting visited links is also a basic operation the user should know.
The user should be able to:
Accessible and usable web pages normally include HTML headings (h-tags). Research shows that navigation by headings is the technique most preferred by screen reader users. The user should be able to:
All screen readers have functionality to move between HTML elements. Typical examples are: buttons, form fields, headings, lists, tables and paragraphs. Exactly which elements can be used for jumping/navigation varies in the different screen readers. The user should be able to:
The virtual search function is useful for finding a specific text on a page. The search text may be found in a link, an alternative text to graphics, hidden text, article text etc. The virtual cursor moves to the search text when this is found. The user should be able to:
Screen readers often use a specific mode when working with forms (at least edit fields). The user should be able to:
Tables may be confusing to the screen reader user, because the screen reader reads the table in a linear fashion, from left to right, as if each table cell begins on a new line. If table headers are used, the screen reader reads them as you move through the table using the table navigation commands. The user must be able to understand the logic of related information in a table, and know the table navigation commands to:
A screen reader user has the possibility of using different strategies to locate information on a web page. The user should be able to use different approaches, depending on the structure of the web site and the task to be solved. The user should be capable of selecting and changing strategy. These strategies include: