Last week, a Monmouth poll found Democrats ahead on its congressional generic ballot by 8 points, 49 percent to 41 percent.

This week, CNN released a poll showing the Dem lead at just 3 points, 47 percent to 44 percent.

But as political scientist Alan Abramowitz notes, the real story of the generic-ballot polling in 2017-2018 is how steady it's been.

"On average, Democrats led by 7.1 points over the past year, and Democrats have led in almost every individual poll. The monthly average ranged from 6.2 points in February 2018 to 10.1 points in December 2017," he writes. “Except for the December results, the monthly averages have fallen within a fairly narrow range of 6.2 to 7.8 points.”

That steadiness is also reflected in the NBC News/Wall Street Journal poll, where the Democratic lead has been anywhere between 6 points and 11 points since the summer of last year.

And what does an average of 6-8 points mean? According to Abramowitz’s prediction model, it puts Democrats in a position to pick up the 23 seats needed to win back the House of Representatives.