About and methods
Where the data comes from and how each number is calculated. Last built November 04, 2026.
Data sources
- Congress.gov API (Library of Congress): Bills, sponsors, cosponsors, and whether a bill became law.
- Voteview (UCLA): Roll call votes and the NOMINATE ideology scores.
- unitedstates/congress-legislators: Member biographies, IDs, parties, and official contact details.
- unitedstates/images: Official member photographs.
How the stats are calculated
Votes cast and missed votes
Counted from recorded roll call votes. Missed means the member did not vote while in office. Absences have many causes, including illness and family emergencies, and this figure does not say why.
Party votes and party unity
A party vote is a roll call where the Democratic majority and the Republican majority took opposite sides. Unity is how often a member sided with their own party's majority on those votes. Independents who caucus with a party are counted with it, and non-voting delegates are left out.
Bills sponsored and bills that became law
Counts bills and joint resolutions only, not simple or concurrent resolutions. A bill counts as law only if it was enacted as its own bill. Text folded into another bill does not count, so the figure understates a member's influence on enacted policy.
Ideology score
A NOMINATE score from Voteview, from -1 (most liberal) to +1 (most conservative), estimated only from how members vote. It describes voting patterns, not personal beliefs. Scores are estimated as fixed across a member's career, and 119th Congress scores are provisional.
Cosponsorship
A cosponsorship is across party lines when the cosponsor and the bill's sponsor are in different parties. The bipartisan law-rate comparison shows association, not cause: bills already likely to move tend to attract support from both sides.
Age
Calculated from birth dates on the day the site was built, for members serving at the time of the latest data download.
Limits to keep in mind
- The 119th Congress is still in progress, so its numbers change.
- Data can contain errors or lag behind official sources. For anything that matters, check Congress.gov, which is the official record.
- Rankings use minimum thresholds (for example, 100 party votes), and members who served only part of a Congress may not appear.
- Contact details are official congressional offices and can change.
About the stories
The Stories section links to news articles. The short summaries are written in our own words with the help of an AI assistant and reviewed before publishing. They can leave out context, so read the original article. Inclusion is not an endorsement, and this site takes no position on candidates, parties, or legislation.