Bridge Grades Data Sources#
Overview
Bridge Grades relies on 10 primary data sources to evaluate congressional collaboration and bipartisanship. Each source measures different aspects of legislative behavior, from bill sponsorship to public communication patterns. This document provides detailed information about each source, how to acquire the data, and how it contributes to the final Bridge Grade calculation.
Primary Data Sources#
1. Plural Policy Bill Sponsorship Data - Sources A & B#
Organization: Plural Policy
Description: Comprehensive bill sponsorship and cosponsorship data for the U.S. Congress, tracking legislative collaboration patterns.
Data Acquisition:
Access: Free download of session-specific CSV files
Format: CSV files with bill sponsorship records
Coverage: Complete bill sponsorship data for current and historical Congresses
Bridge Grades Metrics:
Source A: Authors of Bills with Cross Party Sponsors - Count of sponsored bills with bipartisan cosponsorship
Source B: Ranked People who Cosponsor Bills - Count of bills cosponsored from the opposite party
Current Weight: 3.0 (A), 2.0 (B)
2. Americas Political Pulse (APP) - Sources C, D, E, F#
Organization: Polarization Research Lab
Description: The Polarization Research Lab captures comprehensive data on politicians’ public communications, measuring them across multiple categories including Policy Discussion, Constructive Debate, Personal Attacks, Accomplishments, and Bipartisanship/Compromise.
About the Organization: “A research group and resource hub dedicated to applying science to the study of polarization and democracy. Founded on more than a decade of research by top scholars in the field at Dartmouth College, Stanford University, and the University of Pennsylvania, PRL advances the study of partisan animosity by collecting data, testing new ideas through rigorous science, and sharing the data and findings with others.”
Data Acquisition:
Access: Select “US officials” in left menu, then “Download 2025”
Format: CSV files with communication data
Coverage: All forms of public communication including floor speeches, newsletters, press releases, and social media posts
Bridge Grades Metrics:
Source C: Bipartisan Communication Sum - Total count of bipartisan communications per legislator
Source D: Bipartisan Communication Percentage - Share of total communications that are bipartisan
Source E: Personal Attack Sum - Total count of personal attacks per legislator
Source F: Personal Attack Percentage - Share of total communications that are personal attacks
Current Weight: 1.0 each (C, D, E, F)
3. Cook Political Partisan Voting Index (PVI) - Source M#
Organization: Cook Political Report
Description: Measures how partisan each congressional district and state is relative to the national average. This data rewards bridging behaviors by politicians who represent highly partisan districts as a “degree of difficulty” adjustment.
About the Metric: “We reward bridging behaviors by those who represent highly partisan voting districts as a ‘degree of difficulty.’ This rewards bridging bravery by politicians who could otherwise resort to divider behaviors and still win re-election.”
Data Acquisition:
Access: Paid subscription required
Format: Excel files with district and state-level PVI data
Coverage: All 435 House districts and 50 states for Senate races
Bridge Grades Metrics:
Source M: Cook Political PVI - District/state partisan lean used as multiplier for degree of difficulty
4. VoteView Ideological Scores - Source N#
Organization: VoteView
Description: Provides ideological positioning of members of Congress based on roll-call voting patterns. VoteView allows users to view every congressional roll call vote in American history on a map of the United States and on a liberal-conservative ideological map.
About the Data: “Voteview.com allows users to view every congressional roll call vote in American history on a map of the United States and on a liberal-conservative ideological map including information about the ideological positions of voting Senators and Representatives.”
Data Acquisition:
Website: https://voteview.com/data
Access: Free download
Format: CSV files with member ideology data
Coverage: All members of Congress with ideology scores based on voting patterns
Bridge Grades Metrics:
Source N: VoteView Member Ideology Scores - Absolute distance from ideological center used as multiplier
5. Lugar Bipartisan Index (Conceptual Foundation)#
Organization: Lugar Center
Description: A weighted index that measures bipartisan bill authoring and sponsorship patterns. While not directly used in Bridge Grades calculations, this index provides the conceptual foundation for our bill sponsorship metrics.
About the Index: “A consistently low score on this index will be a very strong indication that a legislator is viewing his or her duties through a partisan lens. Conversely, a consistently high score is a strong indication that a legislator is prioritizing problem solving and open to working with the other party when possible.”
Relationship to Bridge Grades: Our Sources A and B (bill sponsorship metrics) are inspired by and aligned with the Lugar Bipartisan Index methodology.
6. GovTrack Report Cards (Conceptual Foundation)#
Organization: GovTrack
Description: Provides rankings on legislator performance in authoring and co-sponsoring bipartisan legislation. Specifically includes two measures: (1) authoring bills that attract co-sponsors from another party, and (2) co-sponsoring bills authored by a member from another party.
Relationship to Bridge Grades: Our Sources A and B directly implement these two GovTrack measures using Plural Policy data.
Base Data Collection Sources#
Congress.gov API - Master Legislator Roster#
Organization: Congress.gov
Description: Official congressional member data providing the master roster of current legislators with unique bioguide_id identifiers.
Data Acquisition:
Access: Free with API key registration
Format: JSON API responses
Coverage: All current House Representatives and Senators
Bridge Grades Role: Provides the foundational legislator dataset (119th_Congress_20250809.csv) that serves as the master roster for all subsequent data processing and analysis.
OpenStates People Repository - Legislator Biographical Data#
Organization: OpenStates
Description: Comprehensive legislator biographical database with multiple identifier schemes including bioguide_id mappings.
Data Acquisition:
Repository: openstates/people.git
Access: Free, open source
Format: YAML files per legislator
Coverage: Historical and current legislators with comprehensive biographical data
Bridge Grades Role: Enables accurate legislator identification when processing bill sponsorship data from Plural Policy sources by providing bioguide_id mappings.
Data Source Summary Table#
Source |
Organization |
Data Type |
Access |
Current Weight |
Bridge Grades Metric |
|---|---|---|---|---|---|
A |
Plural Policy |
Bill Sponsorship |
Free |
3.0 |
Authors of bills with cross-party sponsors |
B |
Plural Policy |
Bill Cosponsorship |
Free |
2.0 |
Cosponsors of cross-party bills |
C |
Americas Political Pulse |
Communication |
Free |
1.0 |
Bipartisan communication sum |
D |
Americas Political Pulse |
Communication |
Free |
1.0 |
Bipartisan communication percentage |
E |
Americas Political Pulse |
Communication |
Free |
1.0 |
Personal attack sum |
F |
Americas Political Pulse |
Communication |
Free |
1.0 |
Personal attack percentage |
M |
Cook Political |
PVI Data |
Paid |
Bonus |
District partisan lean multiplier |
N |
VoteView |
Ideology Scores |
Free |
Bonus |
Ideological distance multiplier |
P |
Manual |
Caucus Membership |
Manual |
Bonus |
Problem Solvers Caucus bonus |