N. Gregory Mankiw, Economics 10 professor and newly appointed chair of the economics department, could use a refresher on the appropriate citation of sources, according to Nobel Prize-winning economist Paul Krugman in a recent New York Times op-ed. Krugman writes that Mankiw, who is Romney’s lead economic advisor, misused sources in a position paper that he co-wrote with three other economists for the presidential candidate’s campaign.

Mankiw and co. referenced economist Amir Sufi's paper on the 2009 program “Cash for Clunkers” to demonstrate the negative effect of the Obama administration's stimulus policies. Sufi said to Ezra Klein of the Washington Post that his paper does not actually support this point.

“Most of the research is pretty positive on stimulus,” Sufi said to Klein, speaking broadly about research in the field.

Dylan Matthews of the Washington Post notes that there are 15 empirical studies on the effect of the stimulus. Twelve studies note a positive effect. However, these studies are absent from the Romney paper. Instead, the paper cites two studies: the “Cash for Clunkers” paper by Sufi and Atif Mian, which does not make Matthew’s list because it only surveys a small subprogram of the stimulus, and another paper by economist John Taylor, who co-authored the position paper and advises Romney.

Though Mankiw has not directly addressed these claims, co-author Taylor issued a response to Krugman's critique on August 13.

On Sunday, Krugman also called out noted Harvard historian, Niall Ferguson, for allegedly misrepresenting findings of a CBO report on Obama's Affordable Care Act in a cover story for Newsweek. Looks like it's time for everyone to go back to school.