--- title: "Where every number comes from" url: https://politic.design/midterms-2026/methodology/ publisher: politic.design (made by Brantopic) published: 2026-11-05 updated: 2026-11-06 license: CC-BY-4.0 (https://creativecommons.org/licenses/by/4.0/) credit: "Source: politic.design" data: https://politic.design/midterms-2026/methodology/data.json pdf: https://politic.design/midterms-2026/methodology/methodology.pdf --- Methodology · Midterms 2026 # Where every number comes from Each chart, its data, what we did to it and where it can mislead. Every dataset is stored with a content hash, its receipt, so any figure can be recomputed from the same rows. | Chart | Data | Method | Limits | |---|---|---|---| | **Tipping scale** and **ballot** | Group margins for 2020 and 2024 (presidential) and 2026 (House) as published in a widely shared reference chart; group shares of 2026 voters from the [NBC News/SSRS exit poll](https://www.nbcnews.com/politics/2026-elections/exit-polls). | Margins read from pixel positions (about ±1 point). A group's push on the national margin = its share × its swing. The balance point is the share-weighted average margin; the tilt is the turning force around Even, capped at 6°. | Exit polls are estimates; subgroup error runs to several points. Shares are held at their 2026 values, so the balance ignores changes in who turned out. | | **The bill** (receipt) | NBC News/SSRS exit poll, top-issue question and issue items; 122.7m ballots (state tallies compiled by Al Jazeera). | Net votes per issue = share naming it × (D% − R%) × ballots. Because the top-issue shares cover every voter, the lines add up to the national margin. | Says how issue voters split, not what caused their vote. "Also on the tab" items overlap and are not added. | | **The kerb** | NBC News/SSRS exit poll crosstabs. | Margin = D% − R% per group; the band marks ±6 points. | Groups overlap; small groups (4–5% of voters) carry wide error. | | **Covers** | [GDELT DOC 2.0](https://api.gdeltproject.org/api/v2/doc/doc), US English-language sources, 5 Aug–4 Nov 2026, collected by Brantopic. | Daily matching articles ÷ all articles GDELT read that day. Brantopic's quasi-Poisson gate flags days above a 0.1% false-alarm bound, with a 28-day minimum baseline. Cover lines are headlines from each issue's busiest day. | Keyword queries miss some stories and catch some off-topic ones. GDELT covers what it crawls, not all news. | | **Blue wave** city | [The Downballot](https://www.the-downballot.com/p/the-downballots-calculations-of-presidential)'s 2024 presidential results on the 2026 district lines; [CBS News](https://www.cbsnews.com/news/house-districts-flipped-2026-midterm-elections/)'s list of flipped seats (5 Nov). | Uniform swing: a seat is under water when the national shift exceeds Trump's 2024 margin there. Tower layout (shore to inland by margin) is for legibility only. | Dozens of races were uncalled on 5 Nov. Incumbency and candidates make real seats depart from uniform swing. | | **Texas relief** | [Decision Desk HQ](https://votes.decisiondeskhq.com/races/2026-11-03/texas-us-senate-general-election) county results (2026 Senate, 2024 President, 2022 turnout); [us-atlas](https://github.com/topojson/us-atlas) county shapes. | Swing = 2026 Senate margin − 2024 presidential margin. Height ∝ swing; colour = 2026 margin or ballots against 2022. | Senate against President, so part of the swing is the candidates. 41 counties were still counting on 5–6 Nov. | | **Convention** hall | NBC News/SSRS exit poll: recalled 2024 vote × 2026 House vote. | 990 seats, each 0.1% of voters. Turnout effect = margin with the actual 2026 mix of Harris and Trump voters minus the margin with the 2024 mix, holding loyalty rates fixed. | People misremember their past vote, usually toward the winner. To be checked against voter files (Catalist, L2) in 2027. | | **Topline** | Network projections (NBC, CBS, CNN, Yahoo/Newsweek), [Al Jazeera](https://www.aljazeera.com/news/2026/11/5/visualising-how-the-us-midterms-turned-the-map-blue) turnout, [AdImpact](https://thewrap.com/media-platforms/politics/midterm-elections-political-ad-spending-record-2026/) spending. | Taken as reported on 4–6 Nov. | Preliminary until states certify in December. | Sources ## Sources Sources - [NBC News, national exit polls 2026](https://www.nbcnews.com/politics/2026-elections/exit-polls) (SSRS) - [CBS News, House districts that flipped](https://www.cbsnews.com/news/house-districts-flipped-2026-midterm-elections/) - [CBS News, how Democrats won (exit polls)](https://www.cbsnews.com/news/cbs-news-exit-polls-2026-midterms-democrats/) - [CBS News, Senate results](https://www.cbsnews.com/live-updates/senate-election-results-2026/) - [Al Jazeera, turnout and flips](https://www.aljazeera.com/news/2026/11/5/visualising-how-the-us-midterms-turned-the-map-blue) - [Yahoo News, the numbers behind the rout](https://www.yahoo.com/news/politics/article/democrats-2026-midterm-rout-was-big--really-big-here-are-the-numbers-that-prove-it-225923613.html) - [CNN, a historic House majority](https://www.cnn.com/2026/11/05/politics/democrats-house-majority-historic-midterms) - [NPR, six takeaways](https://www.npr.org/2026/11/04/nx-s1-6022216/midterms-democrats-trump-republicans-analysis) - [PBS/AP Voter Poll, key groups](https://www.pbs.org/newshour/politics/ap-voter-poll-how-key-demographic-groups-voted-in-the-2026-midterms) - [Texas Tribune, border counties](https://www.texastribune.org/2026/11/04/texas-border-counties-voter-turnout/) - [Daily Yonder, rural Texas](https://dailyyonder.com/rural-border-communities-fuel-democratic-gains-across-texas/2026/11/05/) - [Axios San Antonio, Latino-majority counties](https://www.axios.com/local/san-antonio/2026/11/04/democrats-win-gop-counties-texas-midterms) - [TheWrap / AdImpact, record ad spending](https://thewrap.com/media-platforms/politics/midterm-elections-political-ad-spending-record-2026/) - [AdImpact party split (via Fox5 Vegas)](https://www.fox5vegas.com/2026/10/29/2026-midterms-set-new-record-political-ad-spending) - [PollCheck, generic-ballot average](https://www.pollcheck.co.uk/us-midterms-2026/generic-ballot) - [Ballotpedia, California redistricting](https://ballotpedia.org/Redistricting_in_California_ahead_of_the_2026_elections) - [GDELT DOC 2.0 API](https://api.gdeltproject.org/api/v2/doc/doc), collected through Brantopic - [Decision Desk HQ, Texas Senate county results](https://votes.decisiondeskhq.com/races/2026-11-03/texas-us-senate-general-election) - [The Downballot, 2024 presidential results on 2026 district lines](https://www.the-downballot.com/p/the-downballots-calculations-of-presidential) - [us-atlas county shapes](https://github.com/topojson/us-atlas) - Swing-chart survey: [Datawrapper on arrow maps](https://www.datawrapper.de/blog/arrow-maps), [Data Viz Project on dumbbells](https://datavizproject.com/data-type/dumbbell-plot), [Visualising Data on the swingometer](https://visualisingdata.com/?p=467), [Cook demographic swingometer](https://www.cookpolitical.com/analysis/survey-research/swingometer/introducing-2024-cook-political-report-demographic-swingometer), [FiveThirtyEight Swing-O-Matic](https://projects.fivethirtyeight.com/2024-swing-the-election) ## The data behind this page ### Data: visual_grammar The ten metaphors used across the gazette. Source: politic.design. | name | idea | form | used_in | |---|---|---|---| | Weight transfer | Groups as weights on the margin ruler; the national margin is where the ruler balances. Under braking a car's load shifts and its balance moves; so does a country's. | 2.5D | Story 1 | | The ballot | The swing counted as filled bubbles on a ballot paper, each contest coloured by the groups that filled it. Separates loud swings from big ones. | 2D | Story 1 | | The kerb | The painted strip at the edge of the track: groups within six points of even, where the next race is won or lost. | 2D | Story 2 | | The receipt | An itemised bill of grievances with a total at the bottom. Also the house style: a source under every number. | 2D | Story 2 | | Cover story | Each issue as a magazine cover, its news-coverage line printed full-bleed behind the headline, with Brantopic's flagged days as hot spots. | 2D | Story 2 | | The blue wave | Districts as a city of towers at their Trump margin; the national swing as a sea that rises through the streets; redrawn maps as levees. | 3D | Story 3 | | Tectonic relief | County swing extruded as terrain. South Texas rises as a new range; the fault lines show where it moved and back. | 3D | Story 4 | | Jet stream | One arrow per county, length and angle set by the swing, so the map reads like a weather front moving across the Sun Belt. | 2D map | Story 4 | | The convention | The electorate as a 990-seat hall: delegations for how people voted last time, flags for how they voted this time, voices from the floor. | 3D | Story 5 | | Pendulum | Every midterm since 1946 as one swing of the president's party. 2026 swings furthest since 1974. Evergreen explainer. | 2.5D | Across the gazette | --- ## License and credit Free to reuse, adapt and republish, including commercially, by any outlet or person, as long as you credit politic.design as the source (with a link to the page where you can). Figures that politic.design took from third parties (exit polls, election results, Wikipedia, GDELT and others named on each dataset) stay under those sources' own terms, so credit them as well. Suggested credit: *Source: politic.design* (https://politic.design/midterms-2026/methodology/). License: [Creative Commons Attribution 4.0 International (CC BY 4.0)](https://creativecommons.org/licenses/by/4.0/). Machine-readable data: https://politic.design/midterms-2026/methodology/data.json