Boundary / Map Data — U.S. Census Bureau TIGER/Line Shapefiles: 2010 vintage for post-2000 Census boundaries (2002–2010 era), 2020 vintage for post-2010 Census boundaries (2012–2020 era) and post-2020 Census boundaries (2022–2024 era). Three boundary sets per chamber. Converted to TopoJSON with polygon winding corrected via Turf.js.
2002–2024 Senate Results —Ballotpedia: District-level results including winner names, party, vote percentages, and margins. Wikipedia Missouri Senate district pages used for cross-verification.
2010–2024 House & General Verification —Ballotpedia and Missouri Secretary of State: Full district-level results with winner names, party, vote percentages, and margins. Historical partisan composition verified against Ballotpedia totals for all years.
Senate Stagger Pattern — Odd-numbered districts (1,3,5…33) contested in years divisible by 4 (2004, 2008, 2012, 2016, 2020, 2024). Even-numbered districts (2,4,6…34) contested in intervening cycles (2002, 2006, 2010, 2014, 2018, 2022). Snapshots reconstruct full 34-seat composition for each cycle.