elections_scorecard_county
Elections scorecard by county combining presidential vote history with demographic context. One row per US county with partisan lean metrics and ranking columns.
tier acomposite_index
overview
overview
All 3,153 US counties. Latest 5 presidential + 4 House cycles for trend metrics.
current vintage — Through 2024 general
history — 5-cycle trailing window from any anchor year
provenance
source & licensing
authority
MIT Election Data and Science Lab
dataset
MIT Election Lab - derived scorecard
source url
methodology
license
Creative Commons Attribution 4.0
citation
MIT Election Data and Science Lab. Derived from County Presidential and US House Returns, 2008-2024.
schema
fields
| name | type | definition |
|---|---|---|
| country_id | string | ISO alpha-2 country code (always 'US' for domestic tables). |
| county_idkey | string | 5-character FIPS code identifying the county.Joins dim.counties on county_id. |
| county_name | string | Human-readable county name corresponding to county_id. |
| house_data_year | int64 | Election year of the most recent U.S. House race used as the reference period for all 'latest' House metrics in this row. |
| house_dem_share_latest | float64 · share (0–1) | Democratic candidate's share of the total U.S. House vote in the county in the most recent House election. Higher values indicate stronger Democratic performance in down-ballot races. |
| house_pres_split_ticket | float64 · percentage points | Difference between the Democratic House vote share and the Democratic presidential vote share (House minus President). Positive values indicate the House Democrat outperformed the presidential candidate, a signal of split-ticket voting behavior. |
| house_pres_split_ticket_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's House-presidential split-ticket measure among all U.S. counties. Higher percentiles indicate a greater tendency for voters to split tickets relative to national peers. |
| house_pres_split_ticket_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's House-presidential split-ticket measure among counties within the same state. Higher percentiles indicate a greater tendency for voters to split tickets relative to in-state peers. |
| median_hh_income | float64 · dollars (nominal) | Median annual household income in the county. Higher values indicate greater typical household economic resources. |
| partisan_lean_index | float64 · index | Composite index of the county's long-run partisan tendency derived from presidential vote history. Positive values indicate Democratic lean; negative values indicate Republican lean; values near zero indicate a balanced partisan history. |
| partisan_lean_index_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's partisan lean index among all U.S. counties. Higher percentiles indicate stronger Democratic lean relative to national peers. |
| partisan_lean_index_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's partisan lean index among counties within the same state. Higher percentiles indicate stronger Democratic lean relative to in-state peers. |
| pct_adults_bachelors_or_higher | float64 · percent (0–100) | Percentage of adults aged 25 and older in the county who hold a bachelor's degree or higher. Higher values indicate a more highly educated adult population. |
| pct_white_nh | float64 · percent (0–100) | Percentage of the county population identifying as white, non-Hispanic. Higher values indicate lower racial and ethnic diversity. |
| political_competitiveness | float64 · index | Index measuring how closely contested elections have been in the county, typically derived from the absolute value or inverse of historical margins. Higher values indicate more competitive, tightly contested races. |
| political_competitiveness_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's political competitiveness index among all U.S. counties. Higher percentiles indicate more closely contested elections relative to national peers. |
| political_competitiveness_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's political competitiveness index among counties within the same state. Higher percentiles indicate more closely contested elections relative to in-state peers. |
| pres_data_year | int64 | Election year of the most recent presidential race used as the reference period for all 'latest' presidential metrics in this row. |
| pres_dem_share_latest | float64 · share (0–1) | Democratic candidate's share of the total presidential vote in the most recent election. Higher values indicate stronger Democratic performance. |
| pres_dem_votes_latest | int64 · count | Total votes cast for the Democratic presidential candidate in the county in the most recent presidential election. |
| pres_margin_avg_5cycles | float64 · percentage points | Simple average of the Democratic presidential margin across the five most recent election cycles. Positive values indicate a historically Democratic-leaning county; negative values indicate Republican lean. |
| pres_margin_avg_5cycles_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's 5-cycle average presidential margin among all U.S. counties. Higher percentiles indicate a more consistently Democratic-leaning county relative to national peers. |
| pres_margin_avg_5cycles_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's 5-cycle average presidential margin among counties within the same state. Higher percentiles indicate a more consistently Democratic-leaning county relative to in-state peers. |
| pres_margin_change_4yr_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's 4-year presidential margin change among all U.S. counties. Higher percentiles indicate a larger Democratic shift relative to national peers. |
| pres_margin_change_4yr_pct_pts | float64 · percentage points | Change in the Democratic presidential margin compared to four years prior (one election cycle). Positive values indicate a shift toward Democrats; negative values indicate a shift toward Republicans. |
| pres_margin_change_4yr_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's 4-year presidential margin change among counties within the same state. Higher percentiles indicate a larger Democratic shift relative to in-state peers. |
| pres_margin_change_8yr_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's 8-year presidential margin change among all U.S. counties. Higher percentiles indicate a larger Democratic shift over two cycles relative to national peers. |
| pres_margin_change_8yr_pct_pts | float64 · percentage points | Change in the Democratic presidential margin compared to eight years prior (two election cycles). Positive values indicate a shift toward Democrats; negative values indicate a shift toward Republicans. |
| pres_margin_change_8yr_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's 8-year presidential margin change among counties within the same state. Higher percentiles indicate a larger Democratic shift over two cycles relative to in-state peers. |
| pres_margin_latest | float64 · percentage points | Democratic minus Republican presidential vote margin in the most recent election. Positive values indicate a Democratic advantage; negative values indicate a Republican advantage. |
| pres_margin_latest_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's latest presidential margin among all U.S. counties nationally. Higher percentiles indicate a more Democratic-leaning margin relative to all other counties. |
| pres_margin_latest_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's latest presidential margin among counties within the same state. Higher percentiles indicate a more Democratic-leaning margin relative to in-state peers. |
| pres_margin_volatility_5cycles | float64 · percentage points | Standard deviation of the Democratic presidential margin across the five most recent election cycles. Higher values indicate greater election-to-election swings in partisan outcome. |
| pres_margin_volatility_5cycles_national_pctile | float64 · percentile (0–100) | Percentile rank of the county's 5-cycle presidential margin volatility among all U.S. counties. Higher percentiles indicate greater electoral swings relative to national peers. |
| pres_margin_volatility_5cycles_state_pctile | float64 · percentile (0–100) | Percentile rank of the county's 5-cycle presidential margin volatility among counties within the same state. Higher percentiles indicate greater electoral swings relative to in-state peers. |
| pres_rep_share_latest | float64 · share (0–1) | Republican candidate's share of the total presidential vote in the most recent election. Higher values indicate stronger Republican performance. |
| pres_rep_votes_latest | int64 · count | Total votes cast for the Republican presidential candidate in the county in the most recent presidential election. |
| pres_total_votes_latest | int64 · count | Total votes cast for all presidential candidates combined in the county in the most recent presidential election. |
| pres_winning_party_latest | string | Party label ('Democrat' or 'Republican') of the candidate who received the most presidential votes in the county in the most recent election. |
| state_id | string | 2-character FIPS code identifying the state.Joins dim.states on state_id. |
relationships
joins
primary key
county_id
common joins
dim.geographies on county_id
demographics_scorecard_county on county_id
economy_scorecard_county on county_id
usage
how to use this table
method
Aggregates per-county presidential and House results to compute partisan_lean_index (avg margin over 5 cycles), pres_margin_volatility_5cycles (stddev), political_competitiveness (1 - |margin|), and house_pres_split_ticket (|house_dem_share - pres_dem_share|).
do not use for
Single-cycle analysis (use base tables); state-level rollups (county is grain - sum requires care for at-large states); causal claims about voter behavior.
known issues
Margin sign convention non-standard (positive = Republican). Volatility metric requires 5 cycles - counties added/redrawn within window may be incomplete.
last updated · May 5, 2026