Every campaign needs to answer: how many votes will be cast, and what will the electorate look like? The Turnout Projection Tool lets you model different turnout scenarios to see how the composition of the electorate changes. Higher turnout brings in different voters than lower turnout—and this shifts the partisan balance in ways that matter for strategy.
Why Turnout Level Matters
The electorate that shows up varies with overall turnout:
- Low-turnout elections (primaries, off-year specials) attract highly engaged, often more partisan voters
- High-turnout elections (presidential generals) bring in infrequent voters who may be less partisan or less predictable
A jurisdiction with D+10 registration might produce a D+15 electorate in a low-turnout primary (if Democratic voters are more engaged) or a D+5 electorate in a high-turnout general (if Republican-leaning infrequent voters show up).
The Projection Tool estimates how the electorate composition changes at different turnout levels, based on historical patterns in that specific jurisdiction.
Finding the Projection Tool
On any jurisdiction page:
- Click the Voters tab
- Select Voter Metrics, then Projection Tool
Using the Tool
The interface has two inputs:
Expected Turnout %: Enter the overall turnout percentage you want to model (e.g., 35%, 50%, 70%).
Election Type: Select General Election or Primary/Special Election. The tool uses historical patterns from similar election types to make its estimates.
The tool displays:
- Historical baseline: The average turnout for the selected election type in this jurisdiction
- Projected Democratic turnout: Estimated share and turnout rate
- Projected Republican turnout: Estimated share and turnout rate
- Projected Other turnout: Estimated share and turnout rate (includes No Party Preference)
What the Projections Show
The tool estimates two things for each party:
Projected Share (% of Electorate): What percentage of voters who show up will be Democrats, Republicans, or Other. This is the composition of the electorate.
Projected Turnout Rate: What percentage of that party's registered voters are expected to vote. This is participation intensity.
These interact: if 80% of Democrats turn out but only 60% of Republicans do, Democrats will be a larger share of the electorate than their registration share suggests.
How It Works
The projection uses a statistical model fit to historical elections in this specific jurisdiction. It accounts for:
- Overall turnout level
- Whether it's a presidential year or not
- The election type (general vs. primary)
- Historical relationships between turnout and partisan composition
The model finds patterns like "when turnout exceeds 60%, Republican share of the electorate tends to increase by X points" and applies those patterns to your scenario.
Scenario Planning Examples
What if turnout is unusually high?
A campaign manager worried about a surge election can model 75% turnout to see how the electorate shifts. If high turnout favors the opposition, they'll know to focus on base mobilization rather than assuming good conditions.
Primary vs. General differences
Compare a 40% primary projection to a 70% general projection for the same jurisdiction. The partisan composition often shifts significantly—useful for candidates facing different opponents in each stage.
Setting vote goals
If you project 45% turnout in a primary, the tool tells you approximately how many total votes will be cast. Combined with the partisan split, you can estimate how many votes your candidate needs to win.
Important Limitations
These are estimates, not predictions. The tool shows what historical patterns imply—not what will actually happen. Unprecedented events, unusual candidates, or major issues can break historical relationships.
The model assumes stable patterns. If the jurisdiction has changed dramatically (new residents, redistricting, demographic shifts), historical patterns may not hold.
Primary elections are less predictable. Lower turnout and more variable participation make primary projections inherently less reliable than general election projections.
The tool doesn't account for specific candidates or issues. A uniquely motivating candidate or ballot measure can drive turnout beyond historical norms.
Small jurisdictions have more uncertainty. With fewer historical data points, the statistical model is less reliable.
Practical Applications
Campaign planning: Estimate the size of the electorate you'll face, then work backward to your vote goal. If you need 50%+1 to win, how many votes is that at 40% turnout? At 55% turnout?
Resource allocation: If high turnout favors your opponent, invest more in early voting and base mobilization. If low turnout favors you, focus on turning out your best supporters rather than expanding the electorate.
Stress-testing assumptions: Run scenarios at turnout levels 10 points above and below your base case. Does your candidate still have a path in the worst-case scenario?
Understanding registration vs. electorate: Registration advantage doesn't equal electoral advantage. Use the tool to see how registration translates to actual voters at different turnout levels.
Common Mistakes
Treating projections as forecasts: The tool helps you plan for scenarios—it doesn't tell you which scenario will happen. Use it alongside other analysis, not as a prediction.
Ignoring the election type: General and primary elections have fundamentally different dynamics. Make sure you've selected the right election type for your analysis.
Assuming linear relationships: Turnout effects aren't always linear. Going from 40% to 50% turnout might change the electorate differently than going from 50% to 60%. Test multiple scenarios.
Forgetting about "Other" voters: No Party Preference voters are a large share of California's electorate. They don't vote as a bloc—their behavior varies by election and jurisdiction.
Using projections without historical context: Before modeling future turnout, look at the Turnout tab to see what turnout actually was in past comparable elections. Ground your scenarios in realistic ranges.