A national poll of likely voters by Emerson College shows Joe Biden losing ground to Donald Trump following the Republican National Convention. Biden still leads. From Emerson:
Trump’s approval at highest point since 2016
General election gap tightening– Biden now leads by 2
Trump continues to lose ground with voters 65 and older
So is this an outlier? Jim Geraghty, writing at National Review, puts it this way:
Nate Silver’s FiveThirtyEight gives Emerson an “A-” grade, so the “this group of pollsters don’t know what they’re doing” probably is not going to fly.