Epistemic Spot Checks is a technique for figuring out the value of a learning resource (usually a book). You can't fact check every single claim in a book, that takes too long. There's a certain amount of trust the reader has to give the author. But how does one know whether an author deserves that trust? Using the Epistemic Spot Checks technique, which Elizabeth created, you read the very beginning of the book (usually a few pages to chapter), take a few claims, and fact check them. If there are too many mistakes in the first pages, you can expect the rest to be the same, if the there are little to no mistakes (especially on something you expected to turn out false), then that author at least gained a few points.
See also: Epistemic Review, Scholarship & Learning