California Political Intelligence · 2026 Cycle
California Political Intelligence · 2026 Cycle
Model the June 2026 Bay Area sales-tax voters to identify and activate November 2026 Bay Area sales-tax voters.
How each precinct voted. Prop 5 is the strongest predictor of Contra Costa sales-tax support.
Projected. Support and Targeting tier are variable — they move with the campaign assumption you set below.
Circle size is the net votes a precinct returns if its turnout rises 10 points — purple gains, orange losses.
A majority-threshold measure is decided by net votes, not ballots. Every 100 additional ballots cast in a precinct that supports the measure 65–35 is worth +30 net votes. The same 100 ballots in a 40–60 precinct is worth −20. So turnout is not a good in itself — it is only good where support already is. The Mobilization value overlay sizes each precinct by exactly that quantity.
| Tier | Precincts | Registered | Projected ballots | Support | Net votes / 100 ballots |
|---|
In June 2026 a Bay Area county inside this five-county footprint put a countywide sales tax on the ballot. It lost, 43.1% to 56.9%, across 656 precincts. That result is the training set: it is a real, recent, precinct-level Bay Area verdict on a sales tax, in the same electorate and the same economy.
Of every variable tested, the strongest predictor by a distance was each precinct's 2024 vote on Proposition 5 — the statewide measure that would have lowered the approval threshold for local infrastructure bonds to 55%. It correlates with the actual sales-tax vote at r = +0.96. Adding Prop 4 (the climate bond) and Prop 36 (the crime measure, which enters negatively) produces a model with R² = 0.928 and a cross-validated error of 3.1 points per precinct.
Partisanship, by contrast, is a materially worse predictor: presidential vote share alone yields R² = 0.63 and roughly double the error. Precincts do not vote on a sales tax the way they vote for president. They vote on it the way they voted on Prop 5.
| Predictor of the real 2026 sales-tax vote | Correlation | Model R² | CV error |
|---|---|---|---|
| Prop 5 2024 — local infrastructure bond threshold | +0.96 | 0.914 | 3.33 pts |
| + Prop 4 (climate bond) + Prop 36 (crime) | — | 0.928 | 3.09 pts |
| Prop 2 2024 — school bond | +0.92 | — | — |
| Presidential vote share 2024 | +0.79 | 0.629 | 6.96 pts |
| Median household income | −0.57 | — | — |
| Renter share of households | +0.53 | — | — |
| Share commuting by transit | +0.50 | — | — |
| Share of registrants 65+ | +0.36 | — | — |
UC Berkeley Statewide Database precinct file (Nov 2024 boundaries, registration, 2024 results); Contra Costa County Registrar of Voters Statement of Vote, June 2 2026; American Community Survey 2019–2023.
Built from the certified voter file, county statements of vote and 2024 results. Ethnicity figures are surname-based estimates. Precinct boundaries are November 2024 SWDB lines.