Right-wing authors’ claims of anti-conservative bias in the New York Times best seller list may not be entirely unfounded, according to a report. A study by The Economist found that books from conservative publishers were on average 7 percent less likely to be included on the list than titles with similar levels of sales from other publishers—though the disparity doesn’t generally affect the top conservative best sellers.

“The New York Times is pure propaganda,” tweeted Elon Musk, a tech mogul, in March. Mr Musk was responding not to the newspaper’s coverage of his companies or of Donald Trump, but rather to the newspaper’s latest bestseller list. “Troubled”, a book by Rob Henderson, a social critic, about the hypocrisy of America’s elite, had been excluded from the hardcover non-fiction list despite selling 3,765 copies in its first week.

The New York Times bestseller list is less likely to include works published by conservative authors even if their books posted sales figures that matched those of left-leaning writers, according to a study.

An analysis conducted by the Economist magazine found that books published by conservative printing houses are 7% less likely to make it onto the Gray Lady’s weekly bestseller list even if those books sell at the same rate as works put out by other publishers.