PLAYGROUND · MP-26 v0.4

Playground

Three tools to test the forecast live: move the national environment and watch both chambers react, paint your own map, or cross any two variables across every county and district.

YOUR SCENARIO

Move the map

National

National swing

Generic-ballot movement; each race absorbs 70%, as in the model.

Polling error

A systematic miss: every race moves by the full amount.

Regional swing

Rust Belt

Sun Belt & South

Middle & Rural

West Coast & Pacific

Mountain West

East Coast

Demographic swing

Hispanic voters

Black voters

White non-college

College graduates

How this works

Every one of the 470 races starts from its published MP-26 v0.4 margin. Your sliders add to it, linearly:

margin = model + national × 0.7 + polling error + region + Σ (group swing × group share)

A group's share is its share of the district's population (the state's, for Senate races) in the Census ACS 2024 5-year profiles. A 10-point Hispanic swing therefore moves a 50% Hispanic district by 5 points and a 5% one by half a point. White non-college is estimated as white share × (1 − bachelor's share). Population shares are not electorate shares, so treat group swings as rough.

Both chambers are then re-simulated in your browser with the model's own engine: a shared national error plus local error for every race. While you drag, 6,000 quick runs; once you stop, the full 50,000.

Simulating…

HOUSE

218 for majority

99%Democratic majority

1%Republican majority

D 248 · 187 RSimulating…

Same as the published forecast

150218 seats320

SENATE

51 for majority

62%Democratic majority

38%Republican majority

D 51 · 49 RSimulating…

Same as the published forecast

3851 seats64

50–50 goes to Republicans: the Vice President breaks ties.

435 DISTRICTS · YOUR SCENARIO

239 districts lean Democratic

RDFlips

Hover a district to compare; click to open its race.

Senate tiles: the 35 seats on the ballot. Grey tiles have no race in 2026.

VS THE PUBLISHED FORECAST

No race changes favourite

Move a slider or pick a preset: races whose expected winner changes appear here.