OZY's Exclusive Election Model: A Democratic House Takeover - OZY | A Modern Media Company

OZY's Exclusive Election Model: A Democratic House Takeover

OZY's Exclusive Election Model: A Democratic House Takeover

By Daniel Malloy


We teamed up with consulting firm 0ptimus to bring a unique projection of how the midterms will go.

By Daniel Malloy

Election projections got it so wrong in 2016 when Donald Trump shocked the world by winning the U.S. presidency. But we don’t want to be caught off-guard again. So to prepare for the topsy-turvy 2018 political season, we here at OZY thought long and hard about how to make our readers smarter about where the country is heading. All year, we’ve delivered extensive on-the-ground coverage of races across the U.S., but we wanted to take it a step further to build a better product to analyze the national political picture.

So we decided to team up with 0ptimus, a data and technology firm based in Washington. Founded in 2013, 0ptimus is a Republican firm — they once worked on Marco Rubio’s presidential campaign — that aimed to develop an unbiased, nonpartisan prediction model so it could show its clients in the worlds of both politics and finance where the winds were blowing.

Our exclusive first forecast shows blue-friendly skies ahead. The Democrats are almost certain to take over the U.S. House this fall, but that doesn’t mean they will have a huge margin to work with in 2019. And the gathering blue wave looks like it will produce a status quo Senate, with Republicans holding onto control by a slim margin.

We find Democrats with an 89.9 percent chance of taking control of the House for the first time since 2010, with the most likely number of Democratic seats at 227, compared with 208 for Republicans.

In the Senate, Republicans have an 82.1 percent chance of capturing at least 50 seats — which is what they’ll need to control the upper chamber, with Vice President Mike Pence acting as a tiebreaker — and we project them to have 51 seats.

0ptimus ozy election forecast report 09 10 2018 1

Alexandria Ocasio-Cortez is one of the surprise candidates who display momentum with their number of small donations.

Source Spencer Platt/Getty

So what’s behind the numbers? Glad you asked. 0ptimus’ data team created and tested countless models, crunching publicly available data against past results in House and Senate races across the country. They take into account more than 100 variables, including past vote totals, generic ballot surveys of which party voters prefer in Congress, the unemployment rate, fundraising data and public polling. The firm developed an artificial intelligence system to “smartly” average together several models to create the strongest prediction numbers for the 2018 elections, always automatically testing against past elections to assess quality. You can read more about the 0ptimus methodology here.


We loved the product 0ptimus put together, but there are some unique factors about 2018 that we think OZY’s predictions should reflect. So we asked 0ptimus to tweak its calculations, adding additional weight to:

  • The number of small donations — a sign of energy for candidates from Trump to Alexandria Ocasio-Cortez.
  • Gender — women are doing exceptionally well this year, and we expect that trend to continue.
  • Trump’s approval rating — as he hangs over the political and media scene with a heavier presence than past presidents.

Meanwhile, we asked 0ptimus to reduce the weight for:

  • Candidate ideology — their calculations rewarded more moderate candidates, while we think this election year is all about firing up the base.
  • Outside money — as OZY has reported, advertising is less persuasive coming from a super-PAC than from a candidate.

Because 0ptimus averages several models, for us they introduced a new Bayesian model to the mix that included Trump approval, gender and unitemized donations, while removing one that included ideology and independent expenditures. The result is the numbers above, which have gotten more Democrat-friendly in recent weeks.

“The national environment continued to shift toward Democrats. They are now very near their high-water mark in 2018,” says 0ptimus data scientist Alex Alduncin, who adds that Democrats hold an 8.8 percentage point advantage. “Most years, that would actually continue to grow between now and Election Day. We’ll see if that’s the case this year.”

The numbers match the increasingly grim outlook we’re seeing for Republicans nationally. But while the OZY/0ptimus model is more confident than some others in a Democratic majority, it likely won’t be as large a majority as the 23-seat margin Republicans now enjoy. This is, in part, because in dozens of states across the country, the GOP controls the redistricting process and has drawn favorable maps, and in part because Democratic voters are more clustered in urban areas.

This geographic disadvantage is more acute in Senate elections this year — in which Democrats are defending 10 states where Trump won in 2016, while Republicans are defending only one Hillary Clinton state. It’s a testament to the strength of Democrats this year that our model predicts a status quo Senate for 2019. The two races considered “tossups” are in deep red states Tennessee and North Dakota. (At this stage, both are projected to go Republican this year.)

Expect more twists and turns to come as the model updates each week with new data, such as fresh polls and fundraising data. And we will be here to track it with you for the next eight weeks until Election Day.

Sign up for the weekly newsletter!

Related Stories