THe following article by Nathaniel Rakich was posted on the FiveThirtyEight.com website August 16, 2018:
One of my favorite FiveThirtyEight concepts is the “tipping-point state,” first introduced by Nate more than 10 years ago. A tipping-point state is a literal swing state: the state that swings the result of a presidential election from one candidate to another. For example, if you put all 50 states in order by the margin that separated Donald Trump and Hillary Clinton in 2016, from most Republican to most Democratic, then went down that list and began counting up the electoral votes for Trump, Wisconsin1 was the state that gave Trump his 270th electoral vote — and therefore the White House.
In the same way, the biennial battle for the U.S. House always has a tipping-point district that determines who gets majority control: the 218th-most-Democratic or most-Republican congressional district in the country (in other words, the median district). Whoever wins the tipping-point district wins the House; it’s that simple.
In addition to all its other bells and whistles, our new U.S. House model can help us estimate the chances that any given congressional district will be the tipping-point district, just like our presidential model estimates which states are most likely to be the tipping point for that race. In first place, the likeliest 2018 bellwether: Minnesota’s 3rd Congressional District. The suburban Minneapolis district went for Hillary Clinton by 9 percentage points in the 2016 election, but it’s home to a strong incumbent in Republican Rep. Erik Paulsen, who won his last election by 14 points and is sitting on a $2.7 million war chest.