This was not McLaughlin's first out-of-whack-with-the-results poll. For instance, a 2013 McLaughlin survey showing Democrat Ed Markey nearly tied in his Massachusetts Senate raceinspired California winemaker John Jordan to plunge $1.4 million of his own money into a super PAC backing Markey's opponent. Markey won by 10 percentage points.
David Nir of Daily Kos Elections compiled a list last year of inaccurate McLaughlin surveys. In October 2012, McLaughlin polls showed Mitt Romney winning in Colorado (by 4 points) and Virginia (by 7 points), even though Romney lost those states by 5 points and 4 points, respectively. In late October 2012, a McLaughlin poll in Rhode Island showed Democratic Sen. Sheldon Whitehouse up by only 8 points against his GOP challenger. Whitehouse won by 30.
Even that poll, though, was more accurate than his last one for Cantor.