Make sure you have a solid grasp of the Pearson General Alternative Text Guidelines and Understanding Image Types before reviewing this Science authoring section. You may also want to review the Math authoring section for guidance on writing alt text for numbers, equations, molecular formulae, and units.
Quick Reminders
- Word choice/terminology: Use the terminology and reading level from the main text.
- The alt text should not give away the answer or provide an unfair advantage to students using assistive technology.
- Image types (e.g., photo, drawing): Do not identify the image type in the alt text unless it’s important for understanding the information in the image.
- The importance of the image type depends on context (i.e., image purpose). For example, if a photo is meant to demonstrate the effects of using certain camera filters, then it should be identified as a “photo.”
- Always identify the following image types at the beginning of the alt text: graphs, line graphs, bar graphs, pie charts, flow charts, tree diagrams, box plots, stem and leaf plots, and micrographs.
- Assessment images: Provide enough information for the student to answer the associated questions. But do not give away the answer. Try to provide an equivalent level of challenge without unnecessarily increasing the cognitive load. For example, the alt text can include the image details related to the correct answer and two distractors.
- Static images used as links to open videos, simulations, or media: The alt text can simply read “Select to launch X” or “Launch X”.
- Tables: Whenever possible, tables should be marked up in HTML. However, there are times when tables must be rendered as images. When necessary, provide alt text and when applicable, long descriptions for the table images.
- Numbers/Symbols/Equations: Refer to the Math section for specific guidance on how to write alt text for these items.
- Superscript and Subscripts
- Denote subscripts and superscripts only when the user needs this information to understand the meaning of the equation.
- When a title comes up for re-edition, STEM elements which include subscripts or superscripts, it is not required to edit previously written descriptions. It is acceptable to maintain the alternative text previously written and follow the “refreshed” guidelines for new alternative text.
- The abbreviation “sub” and “super” are highly recommended for two main reasons:
- Fosters brevity.
- Reduces the alt text character count which is helpful when trying to stay under 255 characters.
In the following examples, subscripts and superscripts are NOT needed to understand the content:
| Math Expression | Alt Text |
|---|---|
| H2O | H 2 O |
| CH4 | C H 4 |
| x5 | x to the fifth power |
| f-1(x) | f inverse of x |
| d2y / dx2 | d 2 y over d x squared |
| 1s22s22p63s23p2 | 1 s 2, 2 s 2, 2 p 6, 3 s 2, 3 p 2 |
In the following examples, subscripts and superscripts are NEEDED to avoid ambiguity:
| Math Expression | Alt Text |
|---|---|
| P1V1=P2V2 | P sub 1 V sub 1 = P sub 2 V sub 2 |
| z1 = r1(cos θ1 + i sin θ1) | z sub 1 equals r sub 1 left paren cosine theta sub 1 plus i sine theta sub 1 right paren |
| anpn + an-1pn-1 + . . . | a sub n p to the n power plus a sub n minus 1 baseline p to the n minus 1 power plus ellipsis |
 | Super 12 sub 6 C |
Platform Authoring Information
Dated: 2024-01-17