Methodology - 2024 U.S. Presidential Election Nowcast

Updated April 22, 2024 at 12:14 AM

View Full Nowcast (Google Sheets)

About the Nowcast

First off, what even is a Nowcast? It's basically just a model that simulates how the election would go if it were today, rather than how it will go on November 5th. By doing this, we get a more real-time idea of where the race stands today, and where polls indicate voters are leaning. I will be updating both the Nowcast and the forecast (once it's released), and both will help determine how the election is going. It's important to note that the Nowcast only uses polls, meaning it can't balance out any polling errors, and this is why it's less reliable. It's also more aggressive and confident in it's outcomes, because it assumes that polls today are as reliable as they should be in November, giving it less uncertainty. Below, I'll briefly explain how the Nowcast works.

Step 1: Create polling averages and state nowcasts

Given that the nowcast is solely reliant on polling, it's essential that I gather and average polls at both the national and state levels in the presidential race. This is explained further at the polling averages page. If a state/district has no polling yet, I use the 2020 results instead.

Step 2: Plug in state odds and run the simulation

This is actually pretty simple: I run a Monte Carlo simulation of 100,000 Electoral College outcomes by telling the model each states Biden/Trump chances, and how many electoral votes they have, and it generates win percentages in terms of who won more simulations, as well as the average electoral votes for both Biden & Trump, the range of outcomes, and more data points. *Note: Although this is a Nowcast, given that uncertainty is fairly low on the state probabilities, I do add in some uncertainty in the simulation as a whole, basically telling it that in each simulation, the winning chances can deviate by up to 25%, assuming there can be error, which adds a bit of uncertainty to the Nowcast overall.

Step 3: Maps, visuals, tables, etc.

That's pretty much it! I then create all necessary maps and fill in tables and content on the model page, and update the charts, and that's the Nowcast! The forecast will be much more complex, and will have it's own methodology.