She’s right. I’m guilty as charged. And it is confusing.
The problem is that I think both uses have value, depending on how you’re interacting with the text. To me, the 5-category system is more relevant for readers . . .
. . . and the 4-category system is more important for writers, especially if you’re writing books for children or using children’s books as mentor texts.
Here’s how I think the two systems are related to one another.
—Traditional nonfiction and browse-able books are almost always survey books. They cover broad topics.
—Expository literature is most frequently STEM concept books, though it can be specialized nonfiction.
—Narrative nonfiction is generally life stories or specialized nonfiction focused on historical events.
—Active nonfiction isn’t quite so easy to pigeonhole, but I’m going to say it’s mostly specialized because most of these books help readers participate in a specific activity.
And so perhaps survey books, concept books, life stories, and specialized nonfiction are best described as subcategories that are most beneficial when writers are considering the best way to present information to their readers. Then, as the writers think about the research process, they can switch gears to focus on which of the five major categories (or which combination of those five) is most likely to contain the information they need.
Maybe the best classification infographic looks like this: