What can legislative cosponsorship data show us about the willingness of members to work across the aisle in Congress? How bipartisan are various Representatives?

Looking at the cosponsorship data to date in the 113th Congress, those Representatives least likely to cosponsor bills authored by Democrats also tend to be names prominently associated with Tea Party or conservative politics. Likewise, some Democrats from more conservative, rural, or Republican-leaning districts co-sponsor more Republican bills than Democratic bills.

Democrats that supported Republican bills did not fare very well in the 2014 elections. Three of the 10 members with the most Republican bills were defeated and an additional three retired. Republicans that stuck to Republican bills were handily reelected, as were Democrats that stuck to Democratic bills. Those Republicans with the highest percentage of Democratic bills also fared well.

As of the current Congressional recess, 6,661* different measures have been introduced in the U.S. House of Representatives. Each of these measures has a chief sponsor who introduced the measure. Of these 6,661 measures, 4,544 have cosponsors who have signed on to the bill in support in addition to the chief sponsor. These are called "cosponsors."

The total number of bills cosponsored by each Representative were calculated. This total was broken down by the party of the lead author of the bill, and from this the percentage of bills authored by congressmen of the Representative’s own party was calculated.

The ends of the spectrum for each party are detailed below.

Download a CSV file for all sitting Representatives here: 113_bipartisan_cospon_data. Please note, this total is current through 2014_11_01, and so it does not include the entirely of the 113th Congress.

Republicans cosponsoring the fewest bills by Democrats (as a percentage of total bills cosponsored)
Representative	Total Bills Cosponsored	Republican Bills Cosponsored	Democratic Bills Cosponsored	% Bills Cosponsored from Own Party	% Vote in 2014 General
Tim Huelskamp (R-KS)	211	208	3	98.58	67.52
Marlin A. Stutzman (R-IN)	154	151	3	98.05	69.16
John Fleming (R-LA)	179	175	4	97.77	73.44
Louie Gohmert (R-TX)	217	212	5	97.70	77.48
Jeb Hensarling (R-TX)	124	121	3	97.58	85.46
Jeff Duncan (R-SC)	320	312	8	97.50	71.36
Tom Graves (R-GA)	147	143	4	97.28	Unopposed
Randy Neugebauer (R-TX)	204	198	6	97.06	77.21
Brad R. Wenstrup (R-OH)	164	159	5	96.95	66.09
Lynn A. Westmoreland (R-GA)	407	393	14	96.56	Unopposed
* * * * *
Republicans cosponsoring the most bills by Democrats (as a percentage of total bills cosponsored)
Representative	Total Bills Cosponsored	Republican Bills Cosponsored	Democratic Bills Cosponsored	% Bills Cosponsored from Own Party	% Vote in 2014 General
Paul Cook (R-CA)	208	151	57	72.60	67.55
Frank R. Wolf (R-VA)	205	147	58	71.71	Retiring
Charles W. Dent (R-PA)	162	116	46	71.60	Unopposed
Don Young (R-AK)	309	219	90	70.87	51.91
Richard L. Hanna (R-NY)	310	211	99	68.06	Unopposed
Michael G. Fitzpatrick (R-PA)	286	191	95	66.78	61.91
Michael G. Grimm (R-NY)	306	201	105	65.69	55.35
Christopher P. Gibson (R-NY)	306	194	112	63.40	64.99
Peter T. King (R-NY)	365	226	139	61.92	68.48
Ileana Ros-Lehtinen (R-FL)	234	134	100	57.26	Unopposed
* * * * *
Democrats cosponsoring the fewest bills by Republicans (as a percentage of total bills cosponsored)
Representative	Total Bills Cosponsored	Republican Bills Cosponsored	Democratic Bills Cosponsored	% Bills Cosponsored from Own Party	% Vote in 2014 General
Barbara Lee (D-CA)	700	92	608	86.86	87.30
Maxine Waters (D-CA)	217	33	184	84.79	70.39
James E. Clyburn (D-SC)	96	15	81	84.38	72.79
Donna F. Edwards (D-MD)	287	45	242	84.32	66.97
Raul M. Grijalva (D-AZ)	772	124	648	83.94	54.71
Donna M. Christensen (D-VI)	272	44	228	83.82	Lost Governor’s Race
Yvette D. Clarke (D-NY)	423	71	352	83.22	89.52
Keith Ellison (D-MN)	646	111	535	82.82	70.90
Steny H. Hoyer (D-MD)	58	10	48	82.76	64.10
Eleanor Holmes Norton (D-DC)	773	138	635	82.15	81.54
* * * * *
Democrats cosponsoring the most bills by Republicans (as a percentage of total bills cosponsored)
Representative	Total Bills Cosponsored	Republican Bills Cosponsored	Democratic Bills Cosponsored	% Bills Cosponsored from Own Party	% Vote in 2014 General
Joe Garcia (D-FL)	233	121	112	48.07	48.50 (lost)
William L. Owens (D-NY)	262	139	123	46.95	Retiring
Henry Cuellar (D-TX)	140	80	60	42.86	82.10
Kurt Schrader (D-OR)	198	117	81	40.91	53.87
Daniel Lipinski (D-IL)	291	172	119	40.89	64.34
Collin C. Peterson (D-MN)	311	187	124	39.87	54.28
Nick J. Rahall II (D-WV)	277	170	107	38.63	44.67 (lost)
John Barrow (D-GA)	164	108	56	34.15	45.22 (lost)
Mike McIntyre (D-NC)	251	171	80	31.87	Retiring
Jim Matheson (D-UT)	215	152	63	29.30	Retiring

* Note: Congress.gov lists 6,672 measures introduced not 6,661 as noted above (The Congress.gov total can be calculated using this link and looking at the total in [brackets] in the upper left hand margin.). The Congress.gov total counts bill numbers that are reserved to the Speaker, Majority Leader, or Minority Leader, but which have not yet been introduced. The figures above exclude those measures and only include bills (H.R.), resolutions (H.Res.), joint resolutions (H.J.Res.) and concurrent resolutions (H.Con.Res). The total does not include amendments (H.Amdt.).

Credits:

• Cosponsorship Data: Congress.gov and previously, thomas.loc.gov
• Data collection and processing: Adam Nordstrom
• Huelskamp image: http://congress.gov/img/member/112_rp_ks_1_huelskamp_tim_200.jpg
• Matheson image: http://congress.gov/img/member/112_matheson_ut02_200.jpg
• Del. Norton election results: https://www.dcboee.org/election_info/election_results/2014/November-4-General-Election
• Del. Christensen election results: http://www.vivote.gov/content/2014-general-election-results
• All other election results: https://www.google.com/search?q=2014+general+election+results