US Election Nowcast – 20th October 2020

Current Nowcast

Although our central point Nowcast has fallen back to 188 EC votes, Trump’s chances of winning in our latest Nowcast have risen slightly. There is slightly more uncertainty in a number of States and this is leading to a wider spread on likely (and not so likely) outcomes.

A number of key States (for example Texas) are woefully under-polled at the moment and we expect to see lots of new data over the next few days to flesh out the position here.

Still not looking as good for Trump as at this point four years ago, but we continue to see signs that the race might yet be tightening.

Probability of Biden Winning State

Presidential Election Forecast Philosophy

Our US Presidential Election forecast is based on polling in individual states. We run a monte-carlo simulation across the entire country and then calculate the probability of each candidate winning each state or electoral district (in the case of Maine and Nebraska). From this we allocate Electoral College votes State by State giving a final total for each candidate.

Do you allocate whole States / Districts to Candidates?

As we approach Election Day, our Nowcast now moves to a full Monte Carlo simulation of the whole country. From this Nowcast onwards our seat forecast is based on allocating the total EC votes for each State / District to the candidate who “wins” in the simulation. From this we produce a probability distribution of likely outcomes.

What do you mean by Strong / Safe / Soft?

We allocate a State a grade on the following basis

Safe – 95% or greater chance of winning or all State’s EC votes allocated to one candidate in EC allocation

Strong – 70% to 95% chance of winning

Soft – 55% to 70% chance of winning

Tie – Less that 55% chance of winning for either candidate

Sites like FiveThirtyEight have a higher probability of Trump winning. What are you doing wrong?

Nothing! 538 uses a different methodology than we do and they are also producing a forecast of polling day, whereas we issue NowCasts (what the result would be today).

Can you tell me what the probability of a certain event happening is?

Sure. We provide the most interesting probabilites above, but it’s easy to calculate things like how likely Biden is to win Texas, Ohio and Florida (3.7% as of this morning). Leave a comment below if there is a particular probability you want us to share with you.