A deluge of data is challenging scientific researchers across disciplines to develop new techniques for detecting patterns in large and complex datasets. This general area of research is known as data-driven discovery, or ‘D3.’ Visualizations are a particularly important area of innovation because they help researchers to investigate complex processes at a more holistic level. The goal of Legislative Explorer is to leverage the same benefits of data-driven visualizations to advance understanding of government.

Anyone can use Legislative Explorer to observe large scale patterns and trends in congressional lawmaking without advanced methodological training. In addition, anyone can dive deeper into the data to further explore a pattern they’ve detected, to learn about the activities of an individual lawmaker, or to follow the progress of a specific bill. Start Exploring!

A few quick tips:

  • Each particle is a congressional bill or resolution
  • When you click on the play arrow to start the animation, you are watching their legislative progress across a two year Congress. There are more than 250,000 bills and resolutions to explore from 1973 to the present.
  • The colors of the particles correspond to the party and chamber of the bill or resolution’s sponsor (red=Republican, blue=Democrat, yellow=Independent)
  • Mousing over a particle provides more information about that bill (you may want to use the slider on the left to get a closer view). Clicking on a bill particle yields additional details, including a link to the bill on
  • Filter options are located at the top. Clicking on ‘more’ reveals additional filter options and the ability to search for a specific bill or resolution in that Congress.
  • Summary statistics are visible at the bottom of the screen.

Some suggestions for where to begin:

  • How many bills are introduced each Congress? How many become law?
  • Have patterns of lawmaking changed since the 1970s? In what ways?
  • A bill that does not become law by the end of a Congress dies. Where do most bills die?
  • What subjects do the bills that become law address?
  • Do successful bill sponsors (sponsors of bills that become law) tend to share any characteristics?
  • Which committees are responsible for tax legislation? Health-related legislation?

As you explore, please keep these limitations in mind:

  • Bills are not Policies. Legislative Explorer only provides information on the progress of bills.
  • Bills vary in importance. Some bills reform the U.S. health care system. Other bills name post offices.
  • The substance of a bill can change dramatically as it moves through the process. As introduced, H.R. 3590 (111th Congress) was six pages long and titled the “Service Members Home Ownership Tax Act of 2009.” When the same bill became law, it was 900 pages long and had a new title, the “Patient Protection and Affordable Care Act of 2009.”
  • Policy proposals can survive after bills die. In 1999, Rep. Martin Meehan introduced H.R. 195, a bill imposing a duty on imported wool trousers. Meehan’s bill died in committee but a bill that did become law sponsored by the committee chairman (H.R. 435) included an identical provision.

Who designed Legislative Explorer?

John Wilkerson (, CAPPP) provided the initial vision; Nick Stramp (, CAPPP) wrangled the extensive underlying data; Christian Marc Schmidt and Sergei Larionov (Schema) converted our rough ideas into a polished product. We had a good time doing it!

Support LegEx

We are pleased to make LegEx freely available but it was not free to develop. Please consider contributing a small amount toward the next phase of development. Specifically, we hope to incorporate information about the changing substance of bill texts as bills move through the process.

Thanks for visiting!

Legislative Explorer draws from an underlying relational database that includes information about the legislative histories, topics and sponsors of more than 250,000 bills and resolutions (1973-present). The database is updated nightly to reflect changes in the status of current bills.

Legislative Explorer data is updated nightly. More detailed descriptions of the data sources and bulk downloads are available at: