Research

General information about Americans Together data sitewide.

Americans Together maps are built to make sense of a complex and constantly shifting U.S. election system. While no central source tracks the full picture, we’ve synthesized data from dozens of reputable sources to provide a comprehensive, nonpartisan view of elections at the national, state, and district level. Given the evolving nature of election law and reporting, our maps reflect the best available information as of publication—and we welcome your feedback. Kindly email info@americanstogether.com.

Section 1: Voter Power Index Methodology

The Voter Power Index is made up of two components: (1) a competitiveness trend score and (2) a structural score. The final Voter Power score is a weighted 70-30 average of the competitiveness trend score plus the structural score.

The scores are indexed to a nominal benchmark of 50, meaning that a value of 50 represents the overall average of the dataset. Indexing the scores allows for a standard benchmark across a range of different datasets. A VPI score above 50 is greater than the national average. A VPI score of 100 represents twice the national average.

Part 1. Competitiveness Trend Score:

2024 and 2020 Presidential Margins (calculated independently)

The calculations place higher values on the most competitive races. Using a 100-point scale, a 0-point margin scores 100, and a 100-point margin scores 0.
Bonuses are added for split ticket districts (where voters choose presidential and congressional winners from different parties)
Example: In an election whose margin was 55% to 45%, the margin score would be 90 (100-raw margin). A split ticket would bump this score up to 95 (as the average of the margin plus a 100 split ticket bonus). The calculated score is indexed against the national average (50).

2024, 2022, and 2020 House Margins (calculated independently)

The calculations place higher values on the most competitive races. Using a 100-point scale, a 0-point margin scores 100, and a 100-point margin scores 0.
Bonuses are added for seats that flipped parties from the prior election.
Example: In an election whose margin was 55% to 45%, the margin score would be 90 (100-raw margin). A flipped seat would bump this score up to 95 (as the average of the margin plus a 100 split ticket bonus). The calculated score is indexed against the national average (50).

Voter Turnout (2024 & 2020):

The calculations place higher values on elections where the percentage of voters in the primary is closest to the percentage who vote in the general election. Using a 100 point scale, elections where the same percentage of voters vote in the primary and general election the score is 100. The 2024 and 2020 scores are averaged and indexed to a mean of 50.

Part 2: Structural Score:

The structural score measures your district’s election rules and voting systems and assigns a score based on how fair or unfair they are. Can independents vote in primary elections? Do candidates need a majority to win an election? Who drew your district boundaries? The more fair and open your district’s elections, the higher its structural score. The below three values are averaged together to come up with one overall average structural score. The results are then indexed to a benchmark mean at 50.

The general election score: Plurality=0, Majority plus top 2 runoff=25, Majority plus runoff=50, Top 2 majority=75, Top 4 majority plus runoff=100
The gerrymandering score: State drawn maps=0, Advisory commissions=50, IRC=100
A primary type score: Closed=0, closed and semi-closed=25, Semi-closed=50, Open=75, Nonpartisan=100

The Voter Power Score then takes the indexed overall competitiveness score and multiplies it by 70%. Then it takes the indexed overall average structural score and multiplies it by 30%. The sum of these two values is the Voter Power score.

VPI Sources:

Section 2: Primaries

The Primaries map uses a number of different sources to determine primary types in each state. Primary systems are varied and nuanced in each state. Many states use different types of primary elections for different offices. When questions arose, we cross-referenced with local sources to determine primary election information. Relying only on public data paints an incomplete picture. Voter registration percentages are unavailable for many states and districts. These percentages constantly change and states which do register voters by party report affiliation percentages at different intervals. We purchased party affiliation percentages at the time of the 2024 general election for every state and congressional district from a third party data provider.

Main Source: https://ballotpedia.org/Primary_election_types_by_state

Section 3: General Elections

Voting systems in each state can be found at: https://ballotpedia.org/Electoral_systems_by_state

Section 4: Gerrymandering

Redistricting processes in each state can be found at: https://gerrymander.princeton.edu/reforms

Section 5: Competitive Races

2024 House Race Results: https://ballotpedia.org/Election_results,_2022:_Congressional_margin_of_victory_analysis

Section 6: Primary Voter Turnout

For the Primary Voter Turnout map, we purchased 2024 voter turnout data and voter registration data from a third party data provider for every state and congressional district. The data reflects voter registration and turnout at the time of the 2024 general election. We also looked at which states held separate congressional and presidential primaries. We relied mainly on state election websites to see where dates differed for congressional and presidential primary elections.

Section 7: Term Limits

Term limits for governor and state legislatures can be found at:

Section 8: Partisan Control

For single party control and state government trifectas: https://ballotpedia.org/State_government_trifectas

For specific composition of state legislatures: https://ballotpedia.org/Historical_partisan_composition_of_state_legislatures#2024_Elections

For supermajorities:https://ballotpedia.org/Veto_overrides_in_state_legislatures

23 states with single party control in 2008: https://ballotpedia.org/State_government_trifectas#trifectastatus-2010-15