We often get asked what signs or numbers we watch to make our 2018 predictions. So we compiled a list of some of the most salient polls and data that we think are the best measures the national political mood.

But sure to bookmark this page. We will update it as new numbers are available.

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1. Presidential Approval

The #1 number that we are checking every day is President Trump's approval rating. It's pretty simple — the lower the president's approval ratings, the more likely it is that the president's party will lose seats in Congress. This is why when there is a very unpopular president, we usually see a wave. 

This week Gallup listed President Trump's approval rating at 40%, with 56% disapproving.

Gallup: Weekly Trump Approval

History tells us that the president's party will lose seats in midterm elections. In the House, the president’s party has lost seats in 35 out of 38 elections (92%) since the end of the Civil War. In the Senate, the president's party has lost seats in 19 out of 26 elections (73%) since 1913 (when the 17th Amendment allowed for direct election of Senators).

When the president is popular (an approval rating of 60% or more), his party has lost, on average, a handful of seats. When the president's approval rating is between 50-60%, the party of the White House has lost an average of 12 seats in the House and one in the Senate. But, when the president's job approval rating is under 50 percent, the party in the White House has lost, on average, 40 House seats and five Senate seats. Trump's approval rating remains under 50 percent (it has hovered between 32-45 for his first term), which does not bode well for Republicans in 2018. 

Historic Presidential Approval Ratings and Seats Lost

Midterm election results have gotten even more volatile in the last 25 years. Four out of the last six midterm elections have resulted in the House, the Senate or both changing parties. In the last six midterm elections, the only years in which the President’s party did not lose either their House or Senate Majority, were 1998 (during Clinton’s impeachment backlash) and 2002 (during the aftermath of 9/11).

Presidential Approval Ratings vs. House Seats Lost

1966 to 2014

2. Intensity Polling

Gallup asks just the basic approve-disapprove question. But other pollsters try to measure intensity, asking those who approve whether they strongly or only somewhat approve and those who disapprove whether they strongly or only somewhat disapprove. 

Those who strongly disapprove of the job Trump is doing as president outnumber those who strongly approve his job performance by a 2-1 margin. According to the latest NBC/WSJ polling, 45% strongly disapprove of President Trump and 32% strongly approve. The intensity of disapproval of President Trump should be very concerning for GOP. Elections are about motivation. And, anger is a very powerful motivator.

Intensity Polling: NBC/WSJ
More on intensity:

3. Congressional Ballot

The "generic ballot" is a poll question that asks voters which party they’d support in the upcoming congressional election. It won't tell us exactly how many seats a party may pick up, but it does show us which party has an advantage. 

House Editor David Wasserman thinks Democrats need to win the national House vote by a seven to eight-point margin to flip the 24 seats they need to take control of Congress.

Current Aggregate Polling Averages — September 28, 2018 Other Polls to Watch



CNNMore on the generic ballot:

4. Independents

In the last three waves, the party that won the House also decisively won the vote of self-described independent voters.

Independent Vote in Midterm Elections

Currently, Trump is polling very poorly with independent voters. Only 34% of them approve of the job he is doing. According to Gallup polling, his highest approval was 42% when he first took office, and his lowest approval point was 29% in early August 2017.

Trump's Approval Among Independents

Going into the last two wave elections in 2006 and 2010, Bush and Obama respectively had poor approval numbers among independents.


More on the independents:

5. Retirements

Incumbents are very hard to beat, even in wave years. For example, in the last four House wave elections (1994, 2006, 2008, and 2010), 59% of House incumbents from the president's party that represented a swing/competitive district (a district with a PVI that favors the other party by 0-5 points) still won. In other words, almost two-thirds of incumbents in some of the most vulnerable seats were able to hold onto them, even in a terrible year for their party. But, when those seats were open seats, the president's party held just 6 percent of those seats. 

    Incumbent Party's Retention Rates in Past Four House Wave* Elections

    In addition to a very unpopular president and anti-GOP sentiment, Democrats need some luck. The last three times the House switched hands — in 1994, 2006 and 2008 — retirements and scandals in previously out-of-reach districts gave the party out of power critical momentum. 

    We're keeping a close eye out for Republican retirements in districts with PVIs between R+5 and D+5. 

    Already this cycle we've moved ratings in the following districts due to retirements: CA-39, CA-49FL-27, NJ-02MI-11WA-08, PA-15

    Subscribers also have access to our list of all open and potentially open seats in the house. Currently, there are 38 open Republican Seats and 21 open Democratic Seats.

    More on the House retirements:

    6. House Math

    Currently, Democrats hold 193 seats and Republicans hold 237 seats in the House. There are six vacancies.

    House Breakdown

    Democrats need to flip 23 seats to take back the house. There are 39 Republican seats rated Toss Up or worse. 

    2018 House Race Ratings (Last Ratings Change September 26, 2018)

    Realistically, Democrats will not win 100% of the seats in Toss Up or worse. In the last three midterm waves (2010, 2006 and 1994) the out party on average won 71% of seats in the Toss Up or worse column.

    How Races in Toss Up or Worse Break in Wave Elections

    Our ratings will change significantly over the course of the next year. But it's important to keep an eye on the number of seats we have in the Toss Up column.

    7. Senate Math

    After Democrats blockbuster win in the Alabama special election, Democrats only need two seats to take the Senate. There are three Republican seats in the Toss Up column: Arizona, Nevada, and Tennessee.

    Senate Breakdown (Last Ratings Change: August 28, 2018)

    While it's possible for Democrats to win the two seats they need, it will also be an uphill battle. Democrats are defending 26 seats compared to Republicans who are only defending nine. Democrats must also defend 10 seats in states that Trump won. And 5 seats that Trump won by 19 points or more. 

    Democratic Exposure in the Senate By 2016 Presidential Results


    Republican Exposure in the Senate By 2016 Presidential Results



    Senior Senate Editor Jennifer Duffy shows that seats in the Toss Up column do not break evenly. One party tends to win a disproportionate share of them.

    The Toss Up Column Does Not Break Evenly

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