MapLight's Core Work

Data Sets       Analysis       Custom Research       Projects


MapLight has three key strengths that, collectively, are not possessed by any other transparency or accountability organization:

  1. We possess a unique, proprietary data set of companies’ and organizations’ support for and opposition to bills in Congress, kept continually up-to-date by MapLight researchers.
  2. We combine multiple data sets in a large-scale way to systematically uncover connections between political inputs and political outputs – i.e. the impact of special interest influence.
  3. We proactively work to ensure that our data is used by accountability actors such as journalists and nonprofit groups to make a real-world impact on public accountability. Our focus on and systems for reaching the public with our data ensure that our data is utilized for accountability purposes instead of just serving academic or general informational purposes.


Data Sets

Only MapLight produces a unique database combining lawmakers’ votes, groups supporting and opposing legislation, and campaign contributions—a database specifically developed to serve increased public accountability.

Our Bill Positions API includes which interest groups, companies, and organizations support and oppose key bills in Congress. For each bill, our in-house research team uses public records sources, like congressional hearing testimony, news databases, and trade associations’ websites, to determine a bill’s supporters and opponents.

Our MapLight Federal Money and Politics Data Set is an easy-to-access, downloadable database featuring MapLight-enhanced Federal Elections Commission campaign finance data and is available for free public use. The data set includes all federal contributions, independent expenditures, and candidate and committee totals, updated regularly with the most current data from the FEC.

Our Federal Lobbying Database provides timely information on unions, companies, and organizations that are lobbying the federal government, including how much money is being spent, which firms are being hired, which issues are being lobbied on, who is being lobbied, and more. This data set is freely available as a searchable Web interface and as a downloadable spreadsheet for deeper analysis.

The Personal Financial Disclosures Search brings to light the the fiscal relationships linking legislators and private companies. Each year, members of Congress file 'personal financial disclosures' (PFDs), detailed lists of their assets and sources of income, including investments. MapLight has compiled and organized these records into a free, searchable data set that can also be downloaded as a spreadsheet.

We have also refined a subset of the California Secretary of State's raw Cal-Access data into the MapLight California Money and Politics Bulk Data Set for quicker, easier use in analyzing contributions to candidates or ballot measure committees in California. The data set is downloadable and available for free public use.

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We work alongside numerous groups who share an interest in transparency and/or political accountability. Most of these groups focus exclusively on tracking or providing public access to various forms of political inputs, such as data sets of campaign contributions or lobbying. Only MapLight is focused on connecting these political inputs to political outputs, such as the outcome of a particular vote, to systematically uncover and publicize instances of special interest influence.

Making these connections is integral to successful public accountability work. In order to mobilize the public to press for accountability around a particular instance of undue influence, or for transformation of our undemocratic campaign finance system, it is necessary to draw the connection between money's influence and its impact.

Read MapLight's latest findings on money and influence here.

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Custom Research

MapLight develops our data, tools, and research services specifically to help journalists and nonprofit groups have public accountability impact. We offer custom research at no cost, provided that the resulting data is used for content that is free to the public.

In the past year alone, MapLight’s research and communications teams fielded a total of 246 requests for custom money and politics data from journalists, nonprofit advocates, activist groups, and others. 
Our transparency tools and research services continue to be used by an ever-wider network of accountability actors to craft bold, urgent calls for change and reform.

See the latest news stories featuring MapLight research here.

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Bill Research

MapLight's Bill Research tool combines bill text and legislative voting records with campaign contributions, making key money and politics information easily accessible with the click of a mouse. Users can apply filters to the data to sort by legislators' political affiliation, interest groups, date range, and types of contributions.

Get started here.

Bill Research


Voter's Edge

Voter's Edge is a one-stop online voter guide providing comprehensive, up-to-date, nonpartisan information about candidates and ballot measures. The site makes it simple for voters to see a customized view of who and what is on their ballots and equips them with the information they need to vote in their own interests.

For the November 2014 election, Voter's Edge covered federal and state-level candidates in all 50 states and statewide ballot measures in every state that has them, greatly simplifying pre-election research for voters across the country. Through a partnership with the League of Women Voters of California Education Fund's Smart Voter, we also covered local candidates and ballot measures for more than 50 California cities and counties. Go to Voter's Edge to get informed about the candidates and ballot measures on your ballot.

Voter's Edge


Influence Tracker

MapLight teamed up with to launch our Influence Tracker widget, which ranks federal candidates by their relative fundraising prowess, revealing the total number of dollars raised by each contender in the past two years and their top 10 contributors.

influence tracker


Data Visualizations

In a continuing collaboration with Tableau Software, MapLight produces interactive data visualizations that make funding information easy to see and share while providing powerful customization tools for journalists and others seeking more sophisticated analyses. See them featured in our research reports here.

MapLight Data Visualizations - 5 million dollar club, top funded Super PACs MapLight Data Visualizations - Leaders of the Super PAC


Politicash Mobile Phone App

MapLight put the power to hold politicians accountable literally in citizens’ hands with our mobile app, Politicash 2012. Freely available for iOS and Android, the app tracked money flowing into the presidential race, making it easier than ever to know exactly who was funding the candidates, including the shadowy sums going into the campaigns of their affiliated super PACs.

Politicash App Politicash App - money raised by Obama and Romney Politicash App - Romney's top supporters

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Learn more about the impact MapLight has made so far.