Gerrymandering

We report several measures of compactness and partisan fairness. They often disagree, and no single number proves a map is gerrymandered — read them together and with the caveats below. Metrics are computed offline from Census TIGER district geometry. Source: TIGER/Line.

Partisan fairness by state

Partisan-fairness measures (efficiency gap, mean–median) need each district's election result on the current (post-2020) boundaries. We don't publish placeholder numbers, so this is pending a sourced House-by-district results dataset; compactness below is already computed from real district geometry. See the sources we use.

Least compact districts

AK-00 Polsby-Popper 0.01 · Reock 0.13 · convex-hull 0.36
NC-03 Polsby-Popper 0.03 · Reock 0.28 · convex-hull 0.47
LA-01 Polsby-Popper 0.03 · Reock 0.32 · convex-hull 0.45

Methodology

Compactness: Polsby-Popper (4π·area/perimeter²), Reock (area / min-bounding-circle), and convex-hull ratio — each 1.0 at most compact. Computed on an equal-area projection (US Albers, EPSG:5070), which is tuned for the contiguous states, so Alaska, Hawaii, and territories are approximate. Fairness: efficiency gap (wasted votes) and mean–median (mean minus median district vote share). Boundaries are versioned by as_of to track court-ordered changes. Ensemble/simulation analysis is planned for a later release.