Four groups of bar graphs on a single x-y axis

Describing Science: Best Practices

Best practices for description of graphs, and tables, and diagrams for individuals who are blind or visually impaired

The National Center for Accessible Media (NCAM) at WBGH in Boston through a grant from the NSF has researched extensively best practices for describing images for the benefit of individuals who are visually impaired.  This research included extensive surveys of STEM professionals and post-secondary students with visual impairment.  The result is a set of image guideline which will prove a valuable resource for Teachers of the Visually Impaired, General Education teachers, parents, and others wishing to accurately describe images for an individual with visual impairment.  Key areas of recommended practice include per NCAM, “brevity, focus on data, clarity and consistency of language, appropriate navigation control and proper use of headers.”

The findings of this research (2004) will be briefly summarized in this blog.  Please refer to the resource itself for a more in-depth description of description: NCAM Image Description Guidelines

Why Is Context Important? 

When describing an image, it is important to consider the context first.  If the image is part of an introduction or purely decorative , it is likely not teaching a concept, and will likely not require much detail.  However, if the image is central to the lesson, it will be necessary to thoroughly describe the image.  If the image is part of an assessment or activity, the describer should consider carefully what specific information will be needed to answer questions or to accurately complete the activity. The age, cultures and expertise of the reader should also be carefully considered as the description is formulated.  

Recommendations for Best Practice

Be Concise

When considering what information to include, use the description from existing captions when possible.  Focus the additional description on information that is not included in the caption and don’t introduce new concepts in the description. Include information on color only when it provides additional vital information.  

Be Objective

Don’t leave out or gloss over unpleasant or controversial information.  

Guidelines for Science Description 

Describing Graphs and Tables

The NCAM guidelines include the following guidelines for describing bar, line, and pie graphs as well as scatter plots.  Again, please refer to the resource itself for more thorough information: NCAM Image Description Guidelines.

Line Graphs and Bar Graphs

When describing either line graphs or bar graphs, begin by giving the title and axes labels to the graph.  Describe X and Y axes labels as follows, “X axis is labeled …..” “Y axis is labeled ……”

The information in the line or bar graph should be converted to an accessible table or provided in a list depending on which format will allow the information to be processed more clearly.  Visual attributes of the graph (color, etc) should only be provided if they are needed to answer a question or for an activity

Pie Graphs

Pie graphs should be presented in an accessible table listing the smallest percentage to greatest no matter how the data is presented in the pie graph.  The title of the Pie Graph should be given to the student in the beginning of the description.

Scatter Plot Graphs

Scatter plots are the most complicated of graphs to describe.  Begin the description with the title and X and Y axes labels. Identify the graph as a scatter plot and focus on describing the change of concentration. If more specific information is needed, provide an accessible table.


If a table is simple enough, it can be presented to the student without any adaptation.  If it is more complex, it should be broken into separate tables. 

Collage of best practices for describing science images

By Laura Hospitál

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