Sim South Dakota: NPN Launches New Election Simulation Model Ahead of 2026 Races

Author: Todd Epp - Northern Plains News

Northern Plains News is launching a new election-analysis project that uses modeled simulations to show how South Dakota’s major 2026 races behave under shifting turnout and support patterns.

The project, called the NPN Race Lab, begins publishing at least monthly updates in December.

The Race Lab tests thousands of modeled scenarios for the South Dakota governor’s race, the U.S. House and U.S. Senate contests, and major statewide ballot measures. The model shows how often each candidate or position finishes first under varying conditions. It does not predict the winner.

NPN built the model using past election returns, county-level turnout data, public polling, and known regional voting patterns. Each simulation generates a new turnout estimate, adjusts support within a realistic range, and calculates shares for each candidate or measure. The results reflect uncertainty and illustrate the structure of each race.

How It Works

NPN runs between one thousand and five thousand simulations for each update. Each run uses:

- A recalculated turnout number

- Adjusted support levels for each candidate or ballot position

- A normalized vote share

- Identification of the top finisher and the margin over the runner-up

The model also tests high-impact scenarios. These include West River turnout surges, elevated suburban participation, evangelical turnout spikes, independent candidates reaching measurable support, and the influence of major statewide ballot issues.

NPN applies small adjustments for prior electoral success, celebrity or identity factors, and candidate-specific volatility. These reflect name recognition, turnout activation, and the wider swings produced by high-profile figures.

Races Covered

The Race Lab will rotate through the most significant South Dakota elections, including:

- The Republican primary for governor

- The U.S. House at-large race

- The U.S. Senate race

- Major statewide ballot measures, including property tax and abortion

- Additional statewide or legislative races with high public interest

What Readers Will See

Each Race Lab installment will include:

- A datelined news story

- The percentage of simulations where each candidate or measure finishes first

- Month-to-month changes

- Results from two or three scenario tests

- Regional notes supported by data

- A standing link to the NPN methodology page

Charts will accompany each report to illustrate simulation outcomes.

Schedule

NPN will publish a Race Lab update at least on the first Monday of each month, beginning in December. As the primary and general elections approach, NPN will increase frequency.

By late summer and fall 2026, NPN will rotate a different race every week, covering governor, U.S. House, U.S. Senate, ballot measures, and other high-interest contests.

Why NPN Built the Race Lab

South Dakota receives limited independent polling, making it difficult to measure early candidate strength or track shifts in key contests. The Race Lab provides a consistent, transparent, and repeatable method for evaluating the state of the race with each update.

The project uses public information, historic behavior, and statistical uncertainty. It measures scenarios, not certainties, and offers readers a clearer view of how political conditions may change in the months ahead.

There will also be a separate page on this site that will explain the methodology in greater detail.