Methodology
How we compile and maintain comprehensive election data for all 50 states, covering nearly 8,000 elected offices.
How we compile and maintain comprehensive election data for all 50 states, covering nearly 8,000 elected offices.
MultiState Elections tracks state-level elected offices across all 50 states. Our database is focused on the 2026 election cycle but includes historical data back to 2010 for trend analysis.
We compile data from a combination of official government sources and established reference databases.
| Source | Data Used | Priority |
|---|---|---|
| Official State Records | Candidate filings, election results, certified outcomes | Primary (always preferred) |
| Ballotpedia | Candidate information, office details, historical elections, biographical data | Secondary reference |
| Secretaries of State | Filing deadlines, candidate lists, ballot measure text | Official source |
| State Legislature Websites | Current member rosters, district information, term data | Official source |
| Sabato's Crystal Ball | Forecast ratings (Solid, Likely, Lean, Toss-Up) | Forecasts |
| Cook Political Report | Forecast ratings for competitive races | Forecasts |
| StateNavigate | State-level election forecasts and competitive race analysis | Forecasts |
| National Conference of State Legislatures | Chamber control history, legislative structure | Historical reference |
| Daily Kos Elections / The Downballot | 2016 presidential results by state legislative district (47 states) | District partisan baselines |
| VEST (Voting and Election Science Team) — Harvard Dataverse | 2016 precinct-level election results (AL, AR, MS) | District partisan baselines |
| U.S. Census Bureau TIGER/Line | State legislative district boundaries (2012 vintage, reflecting post-2010 redistricting) | District partisan baselines |
| OpenElections | Precinct-level election results | Historical reference |
| Redistricting Data Hub | Precinct and block-level election results disaggregated to census geography; district boundary files | Historical reference |
| US Election Atlas | Historical statewide election results by office (Governor, Secretary of State, Attorney General, etc.) back to the 19th century | Historical reference |
| Wikipedia | Historical officeholder lists, biographical data, and election results for statewide offices | Historical reference |
| OpenStates | Current state legislator rosters | Current roster reference |
When sources conflict, we follow a strict hierarchy: official state government records (.gov) are always preferred over third-party compilations. For candidate filing data specifically, we prioritize official Secretary of State or equivalent agency filings over news articles, party websites, or other secondary sources.
Correctly categorizing officeholders by party affiliation requires distinguishing between two concepts:
For maps, charts, and partisan counts, we always use caucus affiliation rather than official party registration. This distinction matters for states like:
A government trifecta exists when one party controls the governorship and both chambers of the state legislature. We classify each state as:
Chamber control is determined by the majority caucus, accounting for vacancies, tied chambers, and power-sharing arrangements on a case-by-case basis.
Election forecast ratings on this site are sourced from Sabato's Crystal Ball (University of Virginia Center for Politics), the Cook Political Report, and StateNavigate. Sabato and Cook use a seven-point scale; StateNavigate uses a nine-point scale that adds Very Likely and Tilt categories.
| Rating | Probability for Leading Party | Description | Sources |
|---|---|---|---|
| Solid D / Solid R | >95% | Not seriously contested; outcome is a near-certainty | All three |
| Very Likely D / Very Likely R | ~90–95% | Strong favorite; only meaningful upset risk under unusual circumstances | StateNavigate only |
| Likely D / Likely R | ~80–90% | Clear favorite with a credible path for the underdog | All three |
| Lean D / Lean R | ~65–80% | Genuine contest; one party has a meaningful but not commanding advantage | All three |
| Tilt D / Tilt R | ~55–65% | Highly competitive; the leading party has only a slight edge | StateNavigate only |
| Toss-up | ~45–55% | No clear advantage for either party; outcome is essentially a coin flip | All three |
Forecast ratings are updated periodically as new information becomes available. Probability ranges above reflect conventional interpretations of each rating tier — the forecasters themselves publish qualitative ratings, not explicit win probabilities. Ratings should be interpreted as expert judgment about the competitive landscape, not statistical predictions.
To provide context for individual district races, we use 2016 presidential election results by state legislative district as a partisan baseline. This is the standard reference point used by election analysts — it captures each district's partisan lean independent of the individual candidates running for that seat.
Compiling district-level presidential results required different approaches depending on state:
Where a precinct crosses a district boundary — a relatively rare but real occurrence — votes are allocated to each district in proportion to the share of the precinct's area falling within that district (area-weighted interpolation). This is the same method used by most academic and journalistic sources for this type of district-level estimation. All geometries were reprojected to the Albers Equal Area CONUS projection (EPSG:5070) for accurate area calculation prior to intersection.
Presidential percentages are expressed as a share of the total vote cast for president in that district (including third-party candidates in the denominator). The margin is calculated as Clinton% minus Trump%, so a negative margin indicates a Trump-carried district.
Election data follows a seasonal rhythm. Our update schedule matches the electoral calendar:
Some states (notably New Hampshire, Vermont, and West Virginia) use multi-member districts where multiple representatives are elected from the same district. In these cases, voters may cast multiple votes, and the top vote-getters win. Our database tracks each seat individually within multi-member districts.
Nebraska's unicameral legislature holds officially nonpartisan elections — candidates do not appear with party labels on the ballot. However, legislators' partisan leanings are well-known, and we track their caucus affiliations for analytical purposes.
Alaska and Maine use ranked-choice voting for certain elections. In Alaska, a top-four open primary feeds into a ranked-choice general election. Our data reflects final certified results after all rounds of tabulation.
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