Election results are reported by county (and precinct) — not by census tract, ZIP code, or custom lines. When a district follows whole counties, its totals are exact sums of official results. Otherwise Civic Knode apportions votes by population: if 38% of a county's people live inside your district, it is credited with 38% of that county's votes. Population weighting (never land-area weighting) is the same method used by professional redistricting tools.

Tract / ZIP / precinct partisan figures are county results disaggregated by each unit's share of its county's 2020 Census population. Congressional and legislative district partisan figures are built by assigning every census tract to its district and rolling those population-weighted shares back up. 2018 and 2022 use total U.S. House votes as the top-of-ticket measure (every House seat is on the ballot in midterms); presidential years use the presidential vote. Senate Scenarios is a what-if painter: it shows which states have a Senate seat up in each cycle (by Senate class) and lets you paint outcomes — it does not contain Senate race results.

Special cases: Alaska reports results by state election district, so county-equivalent figures there are population-weighted estimates of statewide totals. Connecticut's 2016–2022 county-based results are redistributed onto its new planning regions by population. Indiana did not release usable 2018 county detail, so 2018 Indiana figures are statewide estimates. Precinct boundaries and 2020 presidential precinct votes for all 50 states and DC come from the Voting and Election Science Team (VEST, CC-BY 4.0) — these are REAL reported precinct results, not estimates. For other election years (2016, 2018, 2022, 2024), each precinct's result is estimated by scaling its real 2020 vote pattern to the county's actual totals for that year ✱ — a precinct that voted blue in 2020 stays visibly blue in other years. Precinct populations are estimated from vote share ✱. Puerto Rico has no presidential vote, so its partisan figures use Resident Commissioner (U.S. House delegate) results — the delegate's national party affiliation (PNP's González-Colón: Republican; PPD's Hernández: Democrat) determines the D/R mapping, and island-wide totals are distributed across municipios by population ✱. Guam holds no federal partisan election shown here. Median values (age, income) cannot be summed across units and are shown as approximations (~).

The swing slider shifts every unit's two-party share uniformly — a standard uniform-swing model. A what-if tool, not a forecast. Turnout % = total ballots ÷ voting-age population (2020 Census VAP). The Community classification maps USDA Rural-Urban Continuum Codes: 1 = Urban, 2–3 = Suburban, 4–9 = Rural (Civic Knode's simplification). Income coloring uses ACS median household income. Deviation in the District Builder = how far a district's population is from the ideal equal-population size (region population ÷ number of districts).

About 100% results: in midterm House years (2018, 2022), a county lying entirely inside an uncontested district really can show 100% for one party — that is the official result, marked with 🏳, not a data error. Presidential years contain no 0%/100% counties (Civic Knode audits every county in every year for impossible values). 2016 accuracy: county-level 2016 figures are calibrated so every state matches the FEC's certified official totals (fec.gov official results); states needing more than a 5% adjustment (including Alaska, California, New York, Washington and others with late-counted ballots missing from the original compilation) are flagged ✱.