Yale 2026 Election Prediction Competition

Instructions

How to Enter

Steps 1 to 3 are for Yale students outside PLSC 2219; students in the course already have the data and the forecast assignment. Everyone submits the same way, by email (step 4).

  1. Sign upSign up with a Yale email address and a forecaster nickname by Wed., Oct. 28. Spots are limited. You'll get the details of the kickoff event and the election night watch party when you sign up.
  2. Get the dataEntrants receive a shared folder with the course data and an entrant guide covering the files and the forecast format.
  3. Build a forecastPredict the Democratic share of the two-party vote in each of the 470 House and Senate races.
  4. SubmitEmail your forecast.csv by Sunday, Nov. 1, 11:59 pm Eastern. The Submit button opens an email with the details to fill in; attach your file before sending.
Sign up Submit your forecast

Submission

One file, forecast.csv, with a predicted vote share for every race, attached to an email to Prof. DeLuca (step 4). Win probabilities, ranges and simulations are optional.

The entrant guide covers the file format, races with special rules, and a script that checks the file before submission.

Forecast Sites (Optional)

The course website template turns a forecast into a public site like the class model's. To be listed in the gallery under your nickname, say so in your submission email: the gallery shows the files you send, and links to your site if you give its address.

Rules

  • Open to Yale students. One entry per person; entries must be the entrant's own work.
  • Forecasts cover all 470 races.
  • The course data is for use in this competition only and may not be shared.
  • The last forecast emailed before the deadline counts.
  • Prizes go to the most accurate forecasts once the results are in.
  • Entries are listed by nickname. Email addresses are used only for contact and are not posted.

Just for Fun

Not entering the competition but want to make some predictions? Download a blank forecast, type your predictions into the pred_dem_share column, and email it back. Fill in as many races as you like and leave the rest blank. These forecasts aren't part of the competition, but once the results are in you'll get a summary of how accurate you were.

  • Enter the Democratic side's share of the two-party vote (Democrat plus Republican) as a proportion: 0.53 means the Democrat gets 53% and wins by 6 points; 0.47 means they lose by 6.
  • Rows marked "Already filled in" have only one party on the ballot. Leave them as they are.
  • Open the file in Excel, Google Sheets or Numbers, then save or download it as a CSV file.
Download blank forecast.csv Email your forecast

The email button opens a message to with the subject . Attach your file before sending.