Technique G92:Providing long description for non-text content that serves the same purpose and presents the same information

Applicability

Applies to all technologies

This technique relates to 1.1.1: Non-text Content (Sufficient).

Description

The objective of this technique is to provide a long text alternative that serves the same purpose and presents the same information as the original non-text content when a short text alternative is not sufficient.

Combined with the short text alternative, the long description should be able to substitute for the non-text content. The short alternative identifies the non-text content; the long alternative provides the information. If the non-text content were removed from the page and substituted with the short and long descriptions, the page would still provide the same function and information.

In deciding what should be in the text alternatives, the following questions are helpful.

  • Why is this non-text content here?
  • What information is it presenting?
  • What purpose does it fulfill?
  • If I could not use the non-text content, what words would I use to convey the same function and/or information?

Examples

Example 1

A chart showing sales for October has a short text alternative of "October sales chart". The long description would read "Bar Chart showing sales for October. There are 6 salespersons. Maria is highest with 349 units. Frances is next with 301. Then comes Juan with 256, Sue with 250, Li with 200 and Max with 195. The primary use of the chart is to show leaders, so the description is in sales order."

Example 2

A line graph that shows average winter temperatures from the past 10 years includes a short text alternative of "Average winter temperatures 1996-2006." The long description includes the data table that was used to generate the line graph.

Tests

Procedure

  1. Remove, hide, or mask the non-text content
  2. Display the long description
  3. Check that the long description conveys the same information conveyed by the non-text content.

Expected Results

  • #3 is true.