Republican presidential candidate Donald Trump Isaac Brekken | Getty Images

The 2016 presidential election is giving new meaning to the political maxim "It's the economy, stupid." That's because most economists believe that when it comes to formulating growth plans and talking intelligently about the challenges ahead, the candidates primarily have been, well, stupid. Collectively, the field of Hillary Clinton, Bernie Sanders and Donald Trump received a thrashing from a field of economists surveyed by Bankrate.com. Fully half of the 24 experts gave the candidates an "F," with most of the others assigning the group a "D." Respondents groaned both that the candidates' plans were half-baked, and that there is a general lack of attention to serious economic debate during the campaign.

A typical comment: "F. There has been no debate about economic issues during the current presidential campaign," said Mark Zandi, chief economist at Moody's Analytics. There was little charity elsewhere. "'F' grade. Trump's policies are so vacuous, so lacking in detail and void of logic, they are virtually useless. Hillary Clinton's proposals may be more substantive, but she has flip-flopped on issues as well, and is openly pandering to attract Bernie Sanders loyalists. Frankly, Trump and Clinton are the least desirable candidates for the presidency in recent history." — Bernard Baumohl, chief global economist at The Economic Outlook Group.

"'F. Candidates are throwing around utopic polices that are not implementable nor do they address the current issues." — Lindsey Piegza, chief economist, Stifel Fixed Income.

"F. The anti-trade rhetoric and the suggestion we need even more regulation are both notions that would further damage growth." — Sean Snaith, University of Central Florida Institute for Economic Competitiveness. Bill Dunkelberg, chief economist at the National Federation of Independent Business, was among the kindest, giving the candidates a "C." Seth Harris, scholar at Cornell University, said the Democrats deserved an "A" while the GOP side (presumably Trump as he is the sole remaining candidate) scored a "D."