Can you explain more about percentages and why they don’t add up to 100?

Percentages within a category (e.g., BIPOC) and across categories won’t add up to 100% for two reasons.

First, as noted in our explanation of how we count, a book may have characters or content that means it will be counted more than once within a category, as well as across categories. Second, a book may not be counted in a category at all if it doesn’t have content that aligns to what we are documenting. For example, an informational book about electricity wouldn’t be documented in any of the “About” categories, while the creator will only be counted if they are BIPOC, or if we had previously identified them as disabled, LGBTQ, or as a member of a specific religion. There are many books like this that are not counted in a specific “About” category but they are counted as part of the total number we received. 

This is why, across all of our data, it’s important to look at each percentage on its own or in comparison to other percentages in that category rather than assuming the percentages will total 100.

It’s also important not to total percentages—or number of books—in a category and assume that percentage/number represents individual books, or subtract that number from 100 and assume the difference is the percentage/number of all other books we received.