Trump keeps making outlandish claims about GDP

President Donald Trump has claimed multiple times over the past few weeks that GDP would be negative if Hillary Clinton had won the presidency.
"If the Democrats had won the Election in 2016, GDP, which was about 1% and going down, would have been minus 4% instead of up 4.2%," Trump tweeted Monday.
While it's hard to evaluate the claim, the economy prior to the election was resilient, and it's unlikely that such a large downward move would have occurred if Trump did not win.President Donald Trum