Conservative author Dennis Prager responded Wednesday to a series of New York Times public relations department tweets accusing him of “hypocrisy” after he criticized the liberal newspaper’s best seller list’s methodology.

In a CNS News op-ed, Prager notes that, despite ranking near the top of similar best sellers lists published by the Wall Street Journal and Publishers Weekly, and moving more copies than most of the New York Times Best Seller List according to industry sources Nielsen BookScan and Ingram, his new book, The Rational Bible: Exodus, does not appear in any capacity on that most cited of lists.

As he has before, Prager accuses the Times of injecting bias into its rankings, keeping conservative and religious books from taking the coveted title of New York Times Best Seller. He writes:

Few conservatives in the book industry believe that. For example, Regnery Publishing, the publisher of my book, announced a year ago The Times list is so ideologically biased Regnery would no longer announce whether any of its authors are New York Times best-selling authors. And even fewer in the religious community believe it: Does The New York Times regularly include sales data from Christian bookstores, for example?

Prager, who has appeared on the Times list for earlier books, lists himself as a New York Times best selling author in his Twitter profile and elsewhere. This fact is what provoked the Times‘s charge of hypocrisy:

Hypocrisy alert. @DennisPrager wrote a dishonest essay about our best-sellers lists. He claims, “I have long known it isn’t a best-seller list, and I don’t pay attention to it.” Though he lists ”NYT best-selling author” on his twitter bio and his own site. pic.twitter.com/SAm5zanslx — NYTimes Communications (@NYTimesPR) April 18, 2018

Prager freely admits, “Like every author, I write books in the hope that many people will read them, and I know listing “’New York Times best-selling author’ helps sell books.”

In a series of follow-on tweets, the Times attempts to refute Prager’s claims of bias – suggesting, for example that conservative professor Jordan Peterson’s 12 Rules for Life does not appear on their list, as it was published in Canada. Prager disputes this, noting Peterson’s publisher is a Canadian subsidiary of New York-based Random House.

The best seller rankings are notoriously fraught with uncertainty and opportunities for manipulation. Some years ago, the New York Times, for example, started using a cross symbol to indicate a book has been the subject of “bulk orders,” sometimes, according to a 2017 report from left-wing Vox, even removing books based on large order sizes. This affects conservative authors more than others, according to critics.

As Prager reiterates in his piece, his publisher, conservative giant Regnery, de-emphasized the New York Times list last year, and will “no longer announce whether any of its authors are New York Times best-selling authors.”