Jim Behrle lays it out for you. Weekly, the good folks at Harriet put up a post that links back to a list of poetry bestsellers. Where does this list come from? Is this a Publishers' Weekly bestseller list? Does the Poetry Foundation create a list? The word "bestseller" is a dicey supposition to begin with, across any genre. The New York Times bestseller list does ask many bookstores to report their own bestseller lists to contribute to the numbers. But a New York Times bestseller doesn't usually mean more customers bought #1 than #2. When a warehouse at a distributor replenishes another warehouse at a chain, that could count as bestseller numbers. And it's up to the individual reporting store to decide how to report to the New York Times. If a reporting store had events that particular week with Carl Hiaasen and Sloane Crosley, guess who will be at the top of their Bestseller List? Neilsen's Bookscan does not take into account sales at Walmart or Sam...
Like the title says.