The Proportional House — mapping the U.S. House under proportional representation.
How the projection is built: the generic-ballot polling average, Sainte-Laguë seat allocation, per-state elasticity, imputation for uncontested races, and the allocation methods behind the Sandbox (Pure PR, MMD, MMP) — plus the known limitations of each.
This interactive site requires JavaScript. The data is public:
projection.json, the
v1 API, and static per-state pages under /state/.