CNN | 12/16/2018 | Español | Listen

How to look at returns from Pennsylvania 18

Updated 10:54 AM ET, Tue March 13, 2018

(CNN) - The Pennsylvania 18th special congressional election between Democrat Conor Lamb and Republican Rick Saccone is finally here!

The good news for poll watchers, no matter your party affiliation, is it shouldn't be too late a night if the returns come in at the same rate they have in prior years. We should have a clear idea of who has won the race by 11 p.m. ET.

But when polls close at 8 p.m. and results are still coming in, surely the question will be asked: who is winning?

The best way to get at that question is to look at how each candidate is doing in each of the 18th District's four counties and compare that to county benchmarks based off of the past two presidential results.

One candidate may end up winning district-wide by greatly surpassing their benchmarks in one county, despite coming in under their benchmark in another. Still, they are a good starting point to making sense of the results.

Note: all benchmarks are given as what Lamb needs to achieve. To know what Saccone needs to do, just take the opposite (e.g. if Lamb must win a county by 9, then Saccone must lose it by no more than 9. If Lamb cannot afford to lose a county more by than 9, then Saccone must win it by more than 9.)

So, for those following along at home, here's a breakdown of the district's four counties and a general sense of how Lamb and Saccone need to perform in order to claim victory:

Allegheny

It makes up a little more than 40% of the district's voters and is the most Democratic. The county became more Democratic relative to the district as a whole in the 2016 presidential election compared to the 2012 election. Part of that has to do with the fact that this is the most educated part of the district. Hillary Clinton did very well among college educated voters compared to Barack Obama. Based upon the 2012 results, Lamb needs to win only by about 9 points to win district-wide. Based upon the 2016 outcome, Lamb needs to win by at least 16 points. The latest Monmouth University poll, which put Lamb up 6 overall, has Lamb ahead by 24 in this county.

Greene

It only makes about 2% of voters in the district, but Greene County demonstrates how different parts of the district had very different shifts between 2012 and 2016. Greene, which is far less educated than the district as a whole, swung heavily toward Donald Trump in 2016 as did many other places with a number of white voters without a college degree. If the 2016 presidential coalition applies, Lamb can lose here by up to 23 points and still be on track to win the district. If 2012 is a better guide, he can only lose here by up to 8 points.

Washington

It's home to a little more than 20% of the district's voters and is arguably closest to the district's median voter. A recent Monmouth poll illustrates this well. With Lamb up by 6 overall, he is ahead by 2 points in the Greene (again a very small part of the district)/Washington County crosstab. Using the 2012 baseline, Lamb must lose here by less than 1 point to win the race. Using the 2016 baseline, he can afford to lose here by up to 7 points.

Westmoreland

It's home to a little more than 30% of the district's voters and is the Republican counterbalance to Allegheny. Lamb must keep his deficit here to less than 10 points (2012 baseline) or less than 15 points (2016 baseline) in order to emerge victorious district-wide. In the Monmouth poll, Lamb trails here by 14 points. Saccone will have to do better than that if the Monmouth poll is correct about Lamb's strong over-performance in Allegheny.


© 2018 Cable News Network. Turner Broadcasting System, Inc. All Rights Reserved.

Listen to CNN (low-bandwidth usage)

Go to the full CNN experience