Our Forecast: Biden Has a Commanding (But Not Certain) Lead

Our Forecast: Biden Has a Commanding (But Not Certain) Lead

By Scott Tranter and Daniel Malloy

Democratic presidential nominee Joe Biden speaks during a campaign event Sept. 4, 2020, in Wilmington, Delaware.
SourceAlex Wong/Getty


Because these predictions are the best in the business.

By Scott Tranter and Daniel Malloy

Daniel Malloy is OZY’s politics editor. Scott Tranter is founder and CEO of 0ptimus.

This year, against a backdrop of unprecedented global upheaval, OZY is partnering with the data and technology firm 0ptimus to build a better way to forecast the 2020 presidential vote. Election predictions are a tricky business, but learning from the past has helped us launch a new guide to navigate the final weeks of campaigning. These numbers will change, and they’re not gospel, but with Election Day less than two months away, Joe Biden looks poised to be the 46th president of the United States — and the Democrats are substantially favored to control both chambers of Congress.

Our prediction model currently gives Biden an 81 percent chance of winning the presidency, while Democrats have a 76 percent chance of taking a Senate majority and a 98 percent chance of keeping their House majority. You can see a state-by-state and race-by-race breakdown here, where the model will update daily with the freshest data.

Where do the numbers come from? The model crunches a dataset of 200-plus base features spanning from polls to economic conditions to candidate traits to campaign finance reports. For aggregate outcomes, we run millions of simulations using the individual race predictions to derive the range of possible overall outcomes for the electoral college and both chambers of Congress. The electoral college simulations take into account potential correlated errors among states, adjusting for the potential of one candidate sweeping similar states — like President Donald Trump did in 2016 in the Midwest. You can read more about the methodology here.

We worked together to develop an OZY-specific model that increases the weight of small donations — a sign of enthusiasm for a candidate — while decreasing the importance of outside super-PAC spending on a race. We also gave a bump for female candidates, who powered Democrats’ 2018 success, and de-emphasized a score praising ideological moderation, which OZY considered less important in a base-driven election.

Why should you believe the numbers? In 2018, OZY first partnered with 0ptimus, a Republican firm — it worked on Marco Rubio’s presidential campaign — that developed an unbiased, nonpartisan prediction model to better serve its clients in both the political and business worlds. We pegged from the start that Democrats would win the House and Republicans would hold the Senate. And our final forecast was one House seat and one Senate seat off from a perfect score. In January, our model predicted Biden would win the Democratic nomination, which ultimately came to pass, though after some wild swings following the first couple of states.

It’s important to acknowledge uncertainty: If Biden has a 75 percent chance of victory, that means Trump’s odds of triumph are the equivalent of flipping a coin twice and having it come up heads both times. The model anticipates higher turnout this year, but modeling turnout during a pandemic is incredibly difficult — and we don’t know what the virus will look like in swing states by November. We also don’t know if the exceptionally high rate of rejected mail-in ballots in some primaries will hit Democrats hard in what could be a messy count in the weeks following Election Day.

But based on what we do know, our electoral college simulations produce an average outcome of 308 electoral votes for Biden and 230 for Trump, which would be roughly a mirror image of Trump’s victory in 2016. The current presidential toss-up states in our model are Arizona, Florida, Georgia and North Carolina. It is extremely difficult to imagine a path to 270 electoral votes for Trump that does not include Florida. It is also very difficult to envision a scenario where Trump lets Iowa and/or Texas slip away from him but still wins reelection. Both of those states are currently rated Lean Republican, but the more competitive they are, the more precarious Trump’s overall position. 

Similar to 2016, the industrial Midwest presents Trump’s best path to victory, but Michigan, Pennsylvania and Wisconsin all currently lean toward Biden. For Trump to reassert himself in the race, he would need to nudge these Midwestern states closer to him while also not giving up any more ground in the Sun Belt. A burst of polls since the party conventions have led to the model’s overall probability of a Biden victory remaining stable but underlying patterns within specific states shifting (with Florida and Ohio moving toward Trump, while Arizona and Georgia moved toward Biden).

If Biden wins, he will almost certainly have a Democratic Senate to work with. We give Democrats a 76 percent chance of an outright majority, and a 13 percent chance of a 50-50 tie — which would mean effective Democratic control in a Biden win, with new Vice President Kamala Harris breaking ties. The mean outcome of our Senate simulations gives Democrats a 52-48 edge. The current Senate toss-up races are Georgia and Iowa, which both feature Republican incumbents fighting for reelection in races they won by 8 percentage points in 2014. Several more Republican incumbents currently face even tougher odds in their Senate races: Arizona, Maine and North Carolina currently Lean Democrat, while Colorado is rated Likely Democrat.

At 98 percent, the Democrats’ House majority is basically a foregone conclusion. The mean outcome of our House simulations has Democrats winning 235 seats, while Republicans win 200 seats — essentially unchanged from the 2018 outcome. Highlighting the uphill battle Republicans face, 16 of the 25 races currently rated as toss-ups voted Republican in 2018.

If 2020 has shown us nothing else, it’s that more twists and turns lie ahead. Aside from our exclusive election predictions with 0ptimus, OZY will be telling you what’s happening on the ground with America’s fringe movements, conducting revealing interviews with newsmakers, exploring innovative efforts to turn out the vote and much more. Buckle up.