Alternative text or alt-text, is a tough issue for some people to wrap their heads around. In general, it is a description of a picture, table, or graph in a webpage, Word doc, PowerPoint, or PDF. In the past I wrote a primer on alt-text. When we think about math or science, alt-text can become more difficult as sometimes the equations themselves are the image, and need to be described in mathematical or scientific language. Last spring I wrote about the site wide license we acquired for Equatio which can help with some of these issues.
However, I still receive questions, often from people in math and science, about how to write alt-text for an exam when the alt-text might be the correct answer for the question. Sometimes the solution is revamping the question to cover the same idea, but in a slightly different manner. Other times, the solution is more difficult. The NWEA Image Description Guidelines for Assessments should help in these instances. This 116 page guide covers many typical charts, diagrams, and equations used in Math and Science exams, and how to develop good alt-text which will not give away the answer.