Why We Sleep has drawn criticism from Alexey Guzey, an independent researcher with a background in economics, in an essay entitled Matthew Walker's "Why We Sleep" Is Riddled with Scientific and Factual Errors [13], and by Andrew Gelman, a statistician at Columbia University, who in his article called Walker's purported removal of a bar from a graph a "smoking gun," commenting that it entered "research misconduct" territory.[14] Walker has responded to criticisms of the book in an online essay[15].