Fair political polling is a statistical balancing act
Poll: Trump gets convention bump in national poll
The Reuters-Ipsos rolling national poll, which includes data collected from three of the four days of the Republican National Convention, shows Clinton leading Trump by 4 points, 40 percent to 36 percent.
That's a far closer race than the same poll found only one week ago, when Clinton led by 15 points, 46.5 to 31.5.
Trump will officially accept the GOP presidential nomination on the final day of the convention in Cleveland on Thursday night.
The Democratic National Convention, where Clinton will become her party's nominee, kicks off Monday in Philadelphia.
The Reuters-Ipsos survey of 1,522 Americans was conducted between July 16 and 20 has a 3 percentage-point margin of error.