About Members by Interest


Why Members by Interest?

Members of congress vary in many ways, from their background, to their party, to the types of areas they represent. Another important difference is that each member has their own set of personal interests that they bring to their work.

One member may be very interested in farming, while another concerns herself primarily with foreign affairs. It is possible to guess at some of these interests by looking at geographical region or committee assignments, but a more direct route is to examine the types of bills that an individual member sponsors and cosponsors. This is useful information to have, not only to observers of congress, but also for citizens who are especially concerned with a given issue.

How it works

Analysts from the Congressional Research Service look at each bill and resolution and assign them terms from two controlled vocabularies: Policy Area terms and Legislative Subject Terms. The former is a broad overview of the topic of a bill (only one heading is assigned), while the latter is much more granular.

Using the bulk bill status system, information about individual bills are downloaded. Then their subject and policy terms are extracted and matched to member(s) sponsoring and cosponsoring each bill. The resulting data is displayed in two ways — either as a ranked list of members for a given subject, or a graph showing what an individual member is most engaged with.

Adjusted Score

Bills can only have one sponsor, so being that sponsor is a strong indication that one is engaged with the topic(s) addressed by that measure. By contrast, many members can cosponsor a measure, either when it's first introduced (and so perhaps having some influence on a measure's language) or later as it makes its way through the committee process.

For this reason, an "adjusted score" is used to rank the influence of a given member on a particular measure. Members receive one point for sponsoring a bill, 0.2 points for being an orignal cosponsor and 0.1 point for becoming a cosponsor after a measure's introduction. It is these adjusted scores that are added together to rank members by a given subject. They are also used to define the level of a member's engagement with an individual topic.


Bill status data in the format used by Members by Interest currently only exists for the 108th congress onwards. There are current members who started their service before, but activity earlier than the 108th will not be reflected here.

Bill statuses are downloaded and analyzed once per day, so counts for today may lag until then. No attempt is made to independently analyze the "aboutness" of a given bill aside from the headings assigned by CRS.


Members by Interest is a project of Ed Sperr, M.L.I.S.

Ed can be reached at ed_sperr@hotmail.com or esperr@uga.edu.


Members by Interest is powered by JavaScript and jQuery. Code for analyzing bill status data and turning it into a database is written in Python. Data is served from that database by code running on Google App Engine. Google Charts and d3.js are used to draw the charts and responsive layout is made easier with Bootstrap.

You can find the source code for this application as well as the API it uses on GitHub.


Please note that the information provided here comes ultimately from the Government Printing Office.

The code underlying this application is in the Public Domain, but if you use Members by Interest for publication, I'd appreciate a citation:

Sperr E. Members by Interest [Internet]. 2019 [cited your_date_here]. Available from http://esperr.github.io/members-by-interest/

See also...

Want to have even more fun with visualization of congressional data? Check out Committee Flow and Congress by Year