In this example, the data presented in the image is too long or complex for an ALT attribute. Instead, the data is represented in an accessible table on the same page, and the ALT text informs the user of this. Note that data visualizations are generally considered to present accessibility barriers and should be accompanied by either an accessible version of the data or a detailed extended description.

Bar chart as described in this document. Descriptive table follows.
Which of the following are predominant ways in which you have learned about web accessibility?
Response% of Respondents
Formal schooling12.5%
Training or workshops74.8%
Collaboration with peers or colleagues81.1%
Professional conferences59.2%
Meet-ups, camps, unconferences, or other less formal conferences48.7%
On-the-job training or experiences83.4%
Social media48.4%
Books41.2%
Online resources—Stack Overflow, WebAIM.org, etc.91.3%
Other9.8%

ALT: "Bar chart showing methods of learning about web accessibility. Data is represented in the following table."

Source: WebAIM: Survey of Web Accessibility Practitioners #3 Results.