Alternative text is a simple description added to an image that helps individuals using assistive technology understand what the visual image is and its purpose or function so they can fully experience and engage with the digital content or website.

Providing a text description of a chart or graph enhances accessibility and comprehension by summarizing key insights. While the data may be clear to the creator, viewers may struggle to interpret trends, such as “Value A has increased over four years but dropped last quarter.”

Charts and graphs simplify complex information but can be challenging for screen reader users without proper descriptions. To ensure accessibility, always include alt text when using charts or graphs as images in documents.

A text description benefits all users by clarifying:

• Why is the chart or graph important?
• What key information does it convey?
• What is the main takeaway?
• How does it fit into the broader context?

Alt-text ensures clarity and inclusivity, making data accessible to everyone.

• Summarize what is going on in your graph, what conclusions someone can draw from this figure, and why it was important enough to include in your work.  
• Increase the accessibility of your charts by including tabular data in addition to your chart or graph. This allows users accessing your information with a screen reader to still have a way to navigate through your information without missing out on anything.  
• Try to keep your description to less than 80-100 characters. Some screen readers are incompatible with longer alt-text descriptions. 

1. Right-click on the chart, graph, or table and select "Edit Alt Text..."

2. Fill in the information in the newly opened field.

3. A chart, graph, or table should be simple. Try to keep your data as clear and concise as possible.
4. Always consider a basic and accessible color scheme with good color contrast. 

• General Image Description Guidelines
• Specific Image Description Guidelines
• Accessible Digital Charts, Graphs, and Maps!
• Create More Accessible Charts in Excel - Microsoft Support
• Provide Access to Graphs For Users Who Are Blind or Visually Impaired (WGBH Article)
• Describing Science Images for Learners with Disabilities (WGBH Article)