The shapefiles in this folder (<State>_DRA_Mosaic.shp and their sidecar files) are joins of two upstream sources:
precinct-data.csv.Per the LICENSE.txt distributed with each DRA export:
Copyright (c) 2026 Social Good Fund for Dave’s Redistricting.
This data was packaged, and may have been disaggregated and/or aggregated, by Dave’s Redistricting. The data itself came from other sources as noted.
Use of this data is subject to the Creative Commons Attribution-ShareAlike 4.0 International License. Specific datasets may be subject to additional restrictions. (https://creativecommons.org/licenses/by-sa/4.0/)
YOU AGREE NOT TO SELL ANY OF THIS DATA UNDER ANY CIRCUMSTANCES.
Because these shapefiles incorporate DRA-packaged data, they inherit CC BY-SA 4.0 plus DRA’s explicit no-sale restriction. Downstream use must attribute DRA and the upstream election-data providers (below), and any redistribution must be under a compatible ShareAlike license.
LICENSE.txt)| Year(s) | Field | Source |
|---|---|---|
| 2020 | demographics | U.S. Census Bureau (decennial PL 94-171) |
| 2016 | elections | Voting and Election Science Team (VEST) — CC BY 4.0 |
| 2020 | elections | Voting and Election Science Team (VEST) — CC BY 4.0 |
| 2024 | elections | Redistricting Data Hub (RDH) |
These are definitional decisions baked into the joined output, not encoded in DRA’s column names alone:
VAP_BLACK and VAP_ASIAN use the “any-part” definition — i.e. Black/Asian alone or in combination with other races, including Hispanic. This matches DRA’s columns V_20_VAP_Black / V_20_VAP_Asian. The any-part definition is the convention used in Voting Rights Act Section 2 analysis (BVAP / AVAP). DRA also publishes alone-not-Hispanic variants, which this pipeline does not use.
VAP_WHITE is “White alone, not Hispanic” — DRA’s V_20_VAP_White.
VAP_LATINO is “All Hispanics regardless of race” — DRA’s V_20_VAP_Hispanic.
POP_TOTAL is the 2020 decennial census total population — DRA’s T_20_CENS_Total. Not the incarcerated-adjusted variant.
Split-precinct rows — DRA exports represent precincts split across district lines with GEOID20 = B_<parent_GEOID20>_<unique_id>. This pipeline aggregates split rows back to their parent VTD by summing all retained numeric columns, so each output row corresponds to exactly one TIGER VTD polygon.
GEOID set match is strict. If the DRA GEOID set (after split aggregation) does not match the TIGER VTD GEOID set exactly, the state is flagged in join_manifest.csv and no shapefile is written for it. We do not silently drop or zero-fill mismatched rows.
Most <State>_DRA_Mosaic.shp files contain these 14 attributes plus geometry:
| Column | Type | Meaning |
|---|---|---|
| GEOID | string | 11-char VTD GEOID20 (state FIPS + county FIPS + VTD) |
| CTY | string | 3-char county FIPS (positions 3-5 of GEOID) |
| POP_TOTAL | int | 2020 total population |
| VAP_TOTAL | int | 2020 voting age population |
| VAP_WHITE | int | 2020 VAP, White alone not Hispanic |
| VAP_BLACK | int | 2020 VAP, Black any-part |
| VAP_LATINO | int | 2020 VAP, Hispanic (any race) |
| VAP_ASIAN | int | 2020 VAP, Asian any-part |
| TRUMP_24 | int | 2024 presidential — Republican (Trump) votes |
| HARRIS_24 | int | 2024 presidential — Democratic (Harris) votes |
| TRUMP_20 | int | 2020 presidential — Republican (Trump) votes |
| BIDEN_20 | int | 2020 presidential — Democratic (Biden) votes |
| TRUMP_16 | int | 2016 presidential — Republican (Trump) votes |
| CLINTON_16 | int | 2016 presidential — Democratic (Clinton) votes |
Eight states ship with an alternate 2024 schema because precinct-level 2024 results were not available at the time of build: Arkansas, Connecticut, Maine, Michigan, New Jersey, Oklahoma, Oregon, Pennsylvania. In those files, TRUMP_24 and HARRIS_24 are replaced by:
| Column | Type | Meaning |
|---|---|---|
| DT_EST_24 | int | 2024 R (Trump) — county-swing estimate |
| KH_EST_24 | int | 2024 D (Harris) — county-swing estimate |
| EST_24_FLG | string | Estimate flag (currently always scaled) |
Construction: each county’s reported 2020→2024 D/R swing is applied uniformly to every precinct in that county. County-level and state-level sums equal true reported 2024 totals. Per-precinct values are modeled — treat with caution for any analysis that depends on within-county variation.
Three states have precincts removed from the geometry because they are physically isolated from the rest of the state’s polygon graph (offshore islands), which Mosaic’s ReCom cannot handle: California, New York, Rhode Island. Each affects a small population. Hawaii is excluded from the repo entirely for the same reason.
CRS is preserved from the TIGER source: NAD83 (EPSG:4269).
join_manifest.csv in this folder records, per input DRA zip: file, state, status (OK / FLAGGED / ERROR), and detail.