2016 Iowa Republican presidential caucuses


The 2016 Iowa Republican presidential caucuses took place on February 1 in the U.S. state of Iowa, traditionally marking the Republican Party's first nominating contest in their series of Republican Party presidential primaries|presidential primaries] ahead of the 2016 presidential election.
The Democratic Party held its own Iowa caucuses on the same day.
Ted Cruz was able to defeat Donald Trump in the Iowa Caucus by winning over Evangelical caucus-goers; Cruz won 51,666 caucus votes or 27.6%, giving him a net gain of one delegate over Trump. Cruz visited all 99 counties of Iowa and held small events. Cruz outperformed his polling average, which predicted a narrow Trump victory in the caucus.
Following poor performances in the caucuses, Rand Paul, Mike Huckabee and Rick Santorum suspended their campaigns. Both Huckabee and Santorum had previously won the caucus in 2008 and 2012 respectively.

Procedure

According to the Republican Party of Iowa's bylaws, if more than one candidate is nominated at the Republican National Convention, all of Iowa's delegates are bound to vote "proportionally in accordance with the outcome of the Iowa Caucuses" on the first ballot, even if the candidate has withdrawn from the race.
The ballot is a blank piece of paper, and the candidates that voters may vote for in the non-binding preference poll included the following:

Caucus operations

The caucuses began at 7:00 PM local time across 1,681 precincts statewide. After the selection of caucus chairs and secretaries, campaign representatives made speeches supporting their candidates before voters cast their preferences on paper ballots. The 2016 Republican caucuses set a new turnout record with 186,932 participants, significantly higher than the 121,503 who participated in 2012.

Campaign

The Iowa caucuses required extensive ground organization and retail politics from the candidates. Ted Cruz's campaign pursued a traditional grassroots approach, completing the "Full Grassley" by visiting all 99 counties in Iowa while building relationships with evangelical and conservative leaders. His campaign utilized sophisticated data analytics and microtargeting to identify and turn out likely supporters.
Donald Trump opted for a less conventional strategy, focusing on large rallies and earned media coverage that drew thousands of attendees across the state. However, questions persisted about whether his unorthodox approach could successfully convert rally attendance into caucus participation from first-time voters.
Marco Rubio positioned himself as an electable conservative alternative, particularly appealing to suburban voters and party regulars. His campaign emphasized his youth and vision for a "New American Century," gaining momentum in the final weeks before the caucuses.

Forums and debates

November 20, 2015 – Des Moines, Iowa
The Presidential Family Forum was held in the Community Choice Credit Union Convention Center in Des Moines, Iowa. Ben Carson, Ted Cruz, Carly Fiorina, Mike Huckabee, Rand Paul, Marco Rubio, and Rick Santorum attended the forum hosted by evangelical Christian advocacy group The Family Leader. It was hosted by politician and political activist Bob Vander Plaats and moderated by political consultant and pollster Frank Luntz. Protesters interrupted the beginning of the event and were removed by police.
January 28, 2016 – Des Moines, Iowa
The seventh debate was the second debate to air on Fox News. As in Fox's first debate, the moderators were Bret Baier, Megyn Kelly, and Chris Wallace. This was the last debate before actual voting began with the Iowa caucuses on February 1, 2016. Due to personality conflicts with Fox News, Donald Trump opted out of the debate.

Endorsements

Cruz secured several influential endorsements that proved crucial to his victory, including Congressman Steve King, who represented Iowa's 4th congressional district, and Bob Vander Plaats, president of The Family Leader, a prominent evangelical organization.
Trump notably received limited support from Iowa Republican officials, though he led most pre-caucus polls. Meanwhile, Rubio gained important momentum when he received the endorsement of the Des Moines Register and other newspapers in the closing weeks of the campaign.

Polling

Aggregate polls

Poll sourceDate1st2nd3rdOther
Caucus resultsFebruary 1, 2016Ted Cruz
27.64%
Donald Trump
24.30%
Marco Rubio
23.12%
Ben Carson 9.30%, Rand Paul 4.54%, Jeb Bush 2.80%, Carly Fiorina 1.86%, John Kasich 1.86%, Mike Huckabee 1.79%, Chris Christie 1.76%, Rick Santorum 0.95%, Jim Gilmore 0.01%, Other 0.06%
Emerson College
Margin of error: ± 5.6%

Sample size: 298
January 29–31, 2016Donald Trump
27.3%
Ted Cruz
25.6%
Marco Rubio
21.6%
Mike Huckabee 4.7%, Jeb Bush 3.8%, John Kasich 3.8%, Rand Paul 3.4%, Ben Carson 3.4%, Chris Christie 3.2%, Carly Fiorina 1.7%, Rick Santorum 0.5%, Undecided 1%
Quinnipiac University
Margin of error: ± 3.3%
Sample size: 890
January 25–31, 2016Donald Trump
31%
Ted Cruz
24%
Marco Rubio
17%
Ben Carson 8%, Jeb Bush 4%, Rand Paul 4%, Mike Huckabee 3%, Carly Fiorina 2%, John Kasich 2%, Chris Christie 1%, Rick Santorum 1%, Jim Gilmore 0%, Not decided 3%
Opinion Savvy
Margin of error: ± 3.2%

Sample size: 887
January 29–30, 2016Donald Trump
20.1%
Ted Cruz
19.4%
Marco Rubio
18.6%
Ben Carson 9.0%, Rand Paul 8.6%, Jeb Bush 4.9%, Mike Huckabee 4.4%, John Kasich 4.0%, Carly Fiorina 3.8%, Chris Christie 3.0%, Rick Santorum 2.1%, Undecided 2.2%
Des Moines Register/
Bloomberg/Selzer
Margin of error: ± 3.5%
Sample size: 602
January 26–29, 2016Donald Trump
28%
Ted Cruz
23%
Marco Rubio
15%
Ben Carson 10%, Rand Paul 5%, Chris Christie 3%, Jeb Bush 2%, Mike Huckabee 2%, Carly Fiorina 2%, John Kasich 2%, Rick Santorum 2%, Jim Gimore 0%, Undecided 2%, Uncommitted 3%
Public Policy Polling
Margin of error: ± 3.5%
Sample size: 780
January 26–27, 2016Donald Trump
31%
Ted Cruz
23%
Marco Rubio
14%
Ben Carson 9%, Jeb Bush 4%, Mike Huckabee 4%, Rand Paul 4%, Carly Fiorina 3%, John Kasich 2%, Chris Christie 2%, Rick Santorum 1%, Jim Gimore 1%, Undecided 2%
NBC/WSJ/Marist
Margin of error: ± 4.8%
Sample size: 415
January 24–26, 2016Donald Trump
32%
Ted Cruz
25%
Marco Rubio
18%
Ben Carson 8%, Jeb Bush 4%, Carly Fiorina 2%, John Kasich 2%, Rand Paul 2%, Chris Christie 2%, Mike Huckabee 2%, Other 0%, Undecided 3%
Monmouth University
Margin of error: ± 4.4%

Sample size: 500
January 23–26, 2016Donald Trump
30%
Ted Cruz
23%
Marco Rubio
16%
Ben Carson 10%, Jeb Bush 4%, Rand Paul 3%, John Kasich 3%, Mike Huckabee 3%, Chris Christie 2%, Carly Fiorina 2%, Rick Santorum 1%, Jim Gilmore 0%, Other 0%, Undecided 3%
ARG
Margin of error: ± 5.0%

Sample size: 400
January 21–24, 2016Donald Trump
33%
Ted Cruz
26%
Marco Rubio
11%
Ben Carson 7%, Chris Christie 4%, Rand Paul 4%, Jeb Bush 3%, John Kasich 3%, Mike Huckabee 2%, Rick Santorum 1%, Carly Fiorina 1%, Jim Gilmore 0%, Other 1%, Undecided 5%
Quinnipiac University
Margin of error: ± 3.8%
Sample size: 651
January 18–24, 2016Donald Trump
31%
Ted Cruz
29%
Marco Rubio
13%
Ben Carson 7%, Rand Paul 5%, Jeb Bush 4%, Chris Christie 3%, Mike Huckabee 2%, Carly Fiorina 1%, John Kasich 1%, Jim Gilmore 0%, Rick Santorum 0%, Not decided 2%
ISU/WHO-HD
Margin of error: ± ?%

Sample size: 283
January 5–22, 2016Ted Cruz
25.8%
Donald Trump
18.9%
Ben Carson
13.4%
Marco Rubio 12.3%, Rand Paul 6.9%, Jeb Bush 3.8%, Mike Huckabee 3.7%, Carly Fiorina 1.1%, Rick Santorum <1%, Chris Christie <1%, John Kasich <1%
Fox News
Margin of error: ± 5.0%

Sample size: 378
January 18–21, 2016Donald Trump
34%
Ted Cruz
23%
Marco Rubio
12%
Ben Carson 7%, Rand Paul 6%, Chris Christie 4%, Jeb Bush 4%, John Kasich 2%, Mike Huckabee 2%, Rick Santorum 2%, Carly Fiorina 1%, Other 1%, Don't Know 2%
CBS/YouGov
Margin of error: ± 5.9%

Sample size: 492
January 18–21, 2016Donald Trump
39%
Ted Cruz
34%
Marco Rubio
13%
Ben Carson 5%, Rand Paul 3%, Chris Christie 2%, Jeb Bush 1%, John Kasich 1%, Carly Fiorina 1%, Mike Huckabee 0%, Jim Gilmore 0%, No Preference 0%
Emerson College
Margin of error: ± 5.9%

Sample size: 271
January 18–20, 2016Donald Trump
33.1%
Ted Cruz
22.8%
Marco Rubio
14.2%
Ben Carson 9.1%, Chris Christie 5.4%, Jeb Bush 5.1%, John Kasich 2.9%, Rand Paul 2.7%, Carly Fiorina 2.1%, Mike Huckabee 1.7%, Undecided 1%
CNN/ORC
Margin of error: ± 6.0%

Sample size: 266
January 15–20, 2016Donald Trump
37%
Ted Cruz
26%
Marco Rubio
14%
Ben Carson 6%, Jeb Bush 3%, Mike Huckabee 3%, Rand Paul 2%, Carly Fiorina 1%, Rick Santorum 1%, Chris Christie 1%, John Kasich 1%
Monmouth College/KBUR/Douglas Fulmer & Associates
Margin of error: ± 3.7%

Sample size: 687
January 18–19, 2016Ted Cruz
27%
Donald Trump
25%
Ben Carson
11%
Marco Rubio 9%, Jeb Bush 7%, Chris Christie 4%, Mike Huckabee 4%, Rand Paul 3%, John Kasich 3%, Carly Fiorina 3%, Rick Santorum 1%, Jim Gilmore 1%, Undecided 4%
Loras College
Margin of error: ± 4.4%

Sample size: 500
January 13–18, 2016Donald Trump
26%
Ted Cruz
25%
Marco Rubio
13%
Ben Carson 8%, Jeb Bush 6%, John Kasich 4%, Chris Christie 3%, Mike Huckabee 3%, Rand Paul 3%, Carly Fiorina 2%, Rick Santorum 1%, Undecide 7%
Public Policy Polling
Margin of error: ± 4.3%

Sample size: 530
January 8–10, 2016Donald Trump
28%
Ted Cruz
26%
Marco Rubio
13%
Ben Carson 8%, Jeb Bush 6%, Chris Christie 3%, Carly Fiorina 3%, Mike Huckabee 3%, John Kasich 3%, Rand Paul 3%, Rick Santorum 2%, Jim Gilmore 0%, Undecided 2%
DM Register/Bloomberg
Margin of error: ± 4.4%

Sample size: 500
January 7–10, 2016Ted Cruz
25%
Donald Trump
22%
Marco Rubio
12%
Ben Carson 11%, Rand Paul 5%, Jeb Bush 4%, Chris Christie 3%, Mike Huckabee 3%, Carly Fiorina 2%, John Kasich 2%, Rick Santorum 1%
ARG
Margin of error: ± 4.0%
Sample size: 600
January 6–10, 2016Donald Trump
29%
Ted Cruz
25%
Marco Rubio
10%
Ben Carson 8%, Chris Christie 6%, Rand Paul 4%, Jeb Bush 3%, John Kasich 3%, Mike Huckabee 2%, Rick Santorum 2%, Carly Fiorina 1%, Other 1%, Undecided 5%
Quinnipiac University
Margin of error: ± 4.0%
Sample size: 602
January 5–10, 2016Donald Trump
31%
Ted Cruz
29%
Marco Rubio
15%
Ben Carson 7%, Chris Christie 4%, Jeb Bush 3%, Mike Huckabee 3%, Rand Paul 2%, John Kasich 2%, Carly Fiorina 1%, Rick Santorum 1%, Not decided 5%
Fox News
Margin of error: ± 4.0%
Sample size: 504
January 4–7, 2016Ted Cruz
27%
Donald Trump
23%
Marco Rubio
15%
Ben Carson 9%, Jeb Bush 7%, Rand Paul 5%, Chris Christie 4%, Mike Huckabee 2%, Carly Fiorina 1%, John Kasich 1%, Rick Santorum 1%, Other 1%, Undecided 2%
NBC/WSJ/Marist
Margin of error: ± 4.6%
Sample size: 456
January 2–7, 2016Ted Cruz
28%
Donald Trump
24%
Marco Rubio
13%
Ben Carson 11%, Rand Paul 5%, Jeb Bush 4%, Chris Christie 3%, Carly Fiorina 3%, Mike Huckabee 2%, John Kasich 2%, Other 1%, Undecided 3%

Poll sourceDate1st2nd3rdOther
Gravis Marketing
Margin of error: ± 5.0%

Sample size: 440
December 18–21, 2015Donald Trump
31%
Ted Cruz
31%
Marco Rubio
9%
Ben Carson 7%, Jeb Bush 4%, Mike Huckabee 4%, Carly Fiorina 3%, Chris Christie 2%, John Kasich 2%, George Pataki 1%, Lindsey Graham 1%, Rand Paul 1%, Rick Santorum 0%, Unsure 5%
CBS News/YouGov
Margin of error: ± 5.3%

Sample size: 1252
December 14–17, 2015Ted Cruz
40%
Donald Trump
31%
Marco Rubio
12%
Ben Carson 6%, Jeb Bush 2%, Rand Paul 2%, Carly Fiorina 2%, Mike Huckabee 2%, Chris Christie 1%, John Kasich 1%, Rick Santorum 1%, Lindsey Graham 0%, Jim Gilmore 0%, George Pataki 0%, No preference 0%
Public Policy Polling
Margin of error: ± 4.3%

Sample size: 522
December 10–13, 2015Donald Trump
28%
Ted Cruz
25%
Marco Rubio
14%
Ben Carson 10%, Jeb Bush 7%, Carly Fiorina 3%, Chris Christie 3%, Mike Huckabee 3%, Rand Paul 2%, John Kasich 2%, Rick Santorum 1%, Lindsey Graham 1%, Jim Gilmore 0%, George Pataki 0%, Undecided 1%
Quinnipiac University
Margin of error: ± 3.3%

Sample size: 874
December 4–13, 2015Donald Trump
28%
Ted Cruz
27%
Marco Rubio
14%
Ben Carson 10%, Jeb Bush 5%, Rand Paul 4%, Carly Fiorina 3%, Chris Christie 3%, Mike Huckabee 1%, John Kasich 1%, Rick Santorum 0%, George Pataki 0%, Jim Gilmore 0%, Lindsey Graham 0%, DK 3%
Loras College
Margin of error: ± 4.4%

Sample size: 499
December 7–10, 2015Ted Cruz
29.7%
Donald Trump
23.4%
Ben Carson
10.8%
Marco Rubio 10.6%, Jeb Bush 6.2%, Carly Fiorina 3.4%, Rand Paul 2.4%, Mike Huckabee 1.8%, John Kasich 1.0%, Rick Santorum 1.0%, Chris Christie 0.4%, Lindsey Graham 0.0%, Undecided 9.0%
Fox News
Margin of error: ± 4.5%

Sample size: 450
December 7–10, 2015Ted Cruz
28%
Donald Trump
26%
Marco Rubio
13%
Ben Carson 10%, Jeb Bush 5%, Rand Paul 5%, Chris Christie 2%, Carly Fiorina 2%, Mike Huckabee 1%, John Kasich 1%, Rick Santorum 1%, George Pataki 1%, Jim Gilmore 0%, Lindsey Graham 0%, Uncommitted 1%, Other 1%, DK 3%
DMR/Bloomberg
Margin of error: ± 4.9%

Sample size: 400
December 7–10, 2015Ted Cruz
31%
Donald Trump
21%
Ben Carson
13%
Marco Rubio 10%, Jeb Bush 6%, Chris Christie 3%, Mike Huckabee 3%, Rand Paul 3%, John Kasich 2%, Carly Fiorina 1%, Rick Santorum 1%, Jim Gilmore 0%, Lindsey Graham 0%, George Pataki 0%, Uncommitted 3%, Undecided 4%
Monmouth University
Margin of error: ± 4.8%

Sample size: 425
December 3–6, 2015Ted Cruz
24%
Donald Trump
19%
Marco Rubio
17%
Ben Carson 13%, Jeb Bush 6%, Rand Paul 4%, Carly Fiorina 3%, John Kasich 3%, Chris Christie 2%, Mike Huckabee 2%, Rick Santorum 1%, Lindsey Graham <1%, George Pataki 0%, Jim Gilmore 0%, Uncommitted 1%, Undecided 4%
CNN/ORC
Margin of error: ± 4.5%

Sample size: 552
November 28-
December 6, 2015
Donald Trump
33%
Ted Cruz
20%
Ben Carson
16%
Marco Rubio 11%, Jeb Bush 4%, Carly Fiorina 3%, Rand Paul 3%, Chris Christie 2%, Mike Huckabee 2%, John Kasich 1%, Rick Santorum 1%, Lindsey Graham 0%, George Pataki 0%, Jim Gilmore 0%, No one 1%, Someone else 1%, No opinion 1%
Quinnipiac University
Margin of error: ± 4.0%

Sample size: 600
November 16–22, 2015Donald Trump
25%
Ted Cruz
23%
Ben Carson
18%
Marco Rubio 13%, Rand Paul 5%, Jeb Bush 4%, Carly Fiorina 3%, Chris Christie 2%, Rick Santorum 2%, Mike Huckabee 2%, John Kasich 1%, George Pataki 0%, Lindsey Graham 0%, Jim Gilmore 0%, DK/NA 2%
CBS News/YouGov
Margin of error: ± 6.2%

Sample size: ?
November 15–19, 2015Donald Trump
30%
Ted Cruz
21%
Ben Carson
19%
Marco Rubio 11%, Jeb Bush 5%, Carly Fiorina 4%, Chris Christie 2%, Rand Paul 2%, Rick Santorum 2%, Bobby Jindal 2%, John Kasich 1%, Mike Huckabee 1%, George Pataki 0%, Lindsey Graham 0%, Jim Gilmore 0%
Iowa State University/WHO-HD
Margin of error: ± ?

Sample size: 518
November 2–15, 2015Ben Carson
27%
Marco Rubio
17%
Donald Trump
15%
Ted Cruz 9%, Jeb Bush 5%, Rand Paul 3%, Carly Fiorina 2%, Mike Huckabee 1%, John Kasich 1%, Chris Christie 0%, Rick Santorum 0%, Lindsey Graham 0%
CNN/ORC
Margin of error: ± 4.0%

Sample size: 548
October 29 – November 4, 2015Donald Trump
25%
Ben Carson
23%
Marco Rubio
13%
Ted Cruz 11%, Jeb Bush 5%, Carly Fiorina 4%, Bobby Jindal 4%, Chris Christie 3%, Lindsey Graham 2%, John Kasich 2%, Rand Paul 2%, Mike Huckabee 2%, Rick Santorum 0%, George Pataki 0%, Jim Gilmore 0%, No opinion 3%
Gravis Marketing/One America News Network
Margin of error: ± 5.0%

Sample size: 356
October 30 – November 2, 2015Donald Trump
29.4%
Ben Carson
22.4%
Marco Rubio
18.0%
Ted Cruz 8.5%, Jeb Bush 6.0%, Carly Fiorina 5.2%, John Kasich 3.1%, Chris Christie 2.4%, Rand Paul 1.8%, Bobby Jindal 1.5%, Mike Huckabee 1.1%, Rick Santorum 0.4%, Lindsey Graham 0.3%
Public Policy Polling
Margin of error: ± 3.9%

Sample size: 638
October 30 – November 1, 2015Donald Trump
22%
Ben Carson
21%
Ted Cruz
14%
Marco Rubio 10%, Bobby Jindal 6%, Mike Huckabee 6%, Jeb Bush 5%, Carly Fiorina 5%, Chris Christie 3%, Rick Santorum 2%, John Kasich 2%, Rand Paul 2%, Lindsey Graham 0%, George Pataki 0%, Jim Gilmore 0%, Undecided 1%
KBUR/Monmouth University
Margin of error: ± 3.37%

Sample size: 874
October 29–31, 2015Ben Carson
27.5%
Donald Trump
20.4
%
Ted Cruz
15.1%
Marco Rubio 10.1%, Jeb Bush 9.0%, Carly Fiorina 4.1%, Lindsey Graham 0.2%, Mike Huckabee 1.7%, John Kasich 1.9%, Rand Paul 1.6%, Chris Christie 2.3%, Bobby Jindal 1.3%, Rick Santorum 0.7%, Jim Gilmore 0.3%, George Pataki 0%, Undecided 3.8%
Monmouth University
Margin of error: ± 4.9%

Sample size: 400
October 22–25, 2015Ben Carson
32%
Donald Trump
18%
Ted Cruz
10%
Marco Rubio 10%, Jeb Bush 8%, Carly Fiorina 5%, Rand Paul 3%, Bobby Jindal 2%, Mike Huckabee 2%, John Kasich 2%, Rick Santorum 1%, Chris Christie 1%, Lindsey Graham 0%, George Pataki 0%, Jim Gilmore 0%, Other 0%, Uncommitted 1%, Undecided 5%
Loras College
Margin of error: ± 4.4%

Sample size: 500
October 19–22, 2015Ben Carson
30.6%
Donald Trump
18.6%
Marco Rubio
10.0%
Jeb Bush 6.8%, Ted Cruz 6.2%, Bobby Jindal 4.6%, Carly Fiorina 2.4%, Chris Christie 1.8%, Rand Paul 1.8%, John Kasich 1.4%, Mike Huckabee 1.2%, Rick Santorum 0.8%, Lindsey Graham 0.4%, George Pataki 0%, Undecided 12.8%
CBS News/YouGov
Margin of error: ± 6.5%

Sample size: ?
October 15–22, 2015Donald Trump
27%
Ben Carson
27%
Ted Cruz
12%
Marco Rubio 9%, Jeb Bush 6%, Carly Fiorina 3%, Rand Paul 3%, Mike Huckabee 2%, John Kasich 2%, Bobby Jindal 2%, Rick Santorum 2%, Chris Christie 1%, Lindsey Graham 0%, George Pataki 0%, Jim Gilmore 0%, No preference 3%
DMR/Bloomberg
Margin of error: ± 4.9%

Sample size: 401
October 16–21, 2015Ben Carson
28%
Donald Trump
19%
Ted Cruz
10%
Marco Rubio 9%, Rand Paul 5%, Jeb Bush 5%, Carly Fiorina 4%, Mike Huckabee 3%, John Kasich 2%, Bobby Jindal 2%, Rick Santorum 2%, Chris Christie 1%, Lindsey Graham 0%, George Pataki 0%, Jim Gilmore 0%, Not sure 7%, Uncommitted 3%
Quinnipiac University
Margin of error: ± 4.1%

Sample size: 574
October 14–20, 2015Ben Carson
28%
Donald Trump
20%
Marco Rubio
13%
Ted Cruz 10%, Rand Paul 6%, Carly Fiorina 5%, Jeb Bush 5%, John Kasich 3%, Bobby Jindal 3%, Mike Huckabee 2%, Chris Christie 1%, Rick Santorum 1%, Lindsey Graham 0%, George Pataki 0%, Jim Gilmore 0%, Undecided 3%
NBC/WSJ
Margin of error: ± 4.7%

Sample size: 431
October 2015Donald Trump
24%
Ben Carson
19%
Carly Fiorina
8%
Jeb Bush 7%, Ted Cruz 6%, Marco Rubio 6%, Bobby Jindal 6%, Mike Huckabee 5%, Rand Paul 4%, Chris Christie 4%, John Kasich 3%, Rick Santorum 1%, Lindsey Graham 1%, George Pataki <1%, Jim Gilmore <1%, Undecided 7%
Gravis Marketing
Margin of error: ± 4.6%

Sample size: 454
October 2, 2015Donald Trump
18.8%
Ben Carson
14.1%
Ted Cruz
10.6%
Carly Fiorina 9.7%, Marco Rubio 8.9%, Jeb Bush 6.9%, John Kasich 2.6%, Rand Paul 2.4%, Mike Huckabee 1.8%, Lindsey Graham 1.8%, Bobby Jindal 1.7%, Chris Christie 1.4%, Rick Santorum 1.3%, George Pataki 0.3%, Unsure 17.9%
Public Policy Polling
Margin of error: ± 4.4%

Sample size: 488
September 18–20, 2015Donald Trump
24%
Ben Carson
17%
Carly Fiorina
13%
Ted Cruz 8%, Marco Rubio 8%, Mike Huckabee 6%, Jeb Bush 6%, Scott Walker 5%, Rand Paul 4%, Bobby Jindal 4%, John Kasich 2%, Chris Christie 1%, Rick Santorum 1%, George Pataki 0%, Jim Gilmore 0%, Lindsey Graham 0%, Undecided 3%
CBS News/YouGov
Margin of error: ± 5.7%

Sample size: 705
September 3–10, 2015Donald Trump
29%
Ben Carson
25%
Ted Cruz
10%
Marco Rubio 6%, Scott Walker 5%, Carly Fiorina 4%, Mike Huckabee 4%, Rick Santorum 3%, Jeb Bush 3%, Bobby Jindal 2%, John Kasich 2%, Rand Paul 2%, Chris Christie 1%, Jim Gilmore 1%, Lindsey Graham 0%, George Pataki 0%, Rick Perry 0%, No preference 4%
Quinnipiac University
Margin of error: ± 3.0%

Sample size: 1038
August 27September 8, 2015Donald Trump
27%
Ben Carson
21%
Ted Cruz
9%
Jeb Bush 6%, Carly Fiorina 5%, Marco Rubio 5%, John Kasich 5%, Rand Paul 4%, Mike Huckabee 4%, Scott Walker 3%, Bobby Jindal 2%, Chris Christie 1%, Rick Santorum 1%, Rick Perry 1%, Lindsey Graham 1%, George Pataki 0%, Jim Gilmore 0%, Undecided 4%
NBC News/Marist
Margin of error: ± 5.0%

Sample size: 390
August 26 – September 2, 2015Donald Trump
29%
Ben Carson
22%
Jeb Bush
6%
Carly Fiorina 5%, Rand Paul 5%, Scott Walker 5%, Ted Cruz 4%, Marco Rubio 4%, Bobby Jindal 4%, Mike Huckabee 3%, Chris Christie 2%, John Kasich 2%, Rick Santorum 1%, Rick Perry 0%, Lindsey Graham 0%, George Pataki 0%, Jim Gilmore 0%, Undecided 8%
Gravis Marketing/One America
Margin of error: ± 4.4%

Sample size: 507
August 29–31, 2015Donald Trump
31.7%
Ben Carson
15.8%
Ted Cruz
6.9%
Marco Rubio 5.8%, Scott Walker 5.6%, Bobby Jindal 5.2%, Carly Fiorina 4.6%, Jeb Bush 4.1%, Mike Huckabee 2.6%, Chris Christie 2.0%, John Kasich 1.4%, Rand Paul 1.3%, Rick Perry 0.9%, Rick Santorum 0.6%, Lindsey Graham 0.4%, George Pataki 0.1%, Undecided 10.9%
Monmouth University
Margin of error: ± 4.9%

Sample size: 405
August 27–30, 2015Donald Trump
23%
Ben Carson
23%
Carly Fiorina
10%
Ted Cruz 9%, Scott Walker 7%, Jeb Bush 5%, John Kasich 4%, Marco Rubio 4%, Rand Paul 3%, Rick Santorum 2%, Bobby Jindal 1%, Chris Christie 1%, Rick Perry 1%, George Pataki 0%, Jim Gilmore 0%, Lindsey Graham 0%, Someone else 0%, Undecided 5%
Des Moines Register/Bloomberg/Selzer
Margin of error: ± 4.9%

Sample size: 400
August 23–26, 2015Donald Trump
23%
Ben Carson
18%
Ted Cruz
8%
Scott Walker 8%, Jeb Bush 6%, Marco Rubio 6%, Carly Fiorina 5%, Mike Huckabee 4%, Rand Paul 4%, Chris Christie 2%, Bobby Jindal 2%, John Kasich 2%, Rick Perry 1%, Rick Santorum 1%, George Pataki 0%, Jim Gilmore 0%, Lindsey Graham 0%, Someone else 0%, Undecided 10%
CNN/ORC
Margin of error: ± 2%

Sample size: 2,014
August 7–11, 2015Donald Trump
22%
Ben Carson
14%
Scott Walker
9%
Ted Cruz 8%, Carly Fiorina 7%, Mike Huckabee 7%, Jeb Bush 5%, Rand Paul 5%, Marco Rubio 5%, Chris Christie 3%, Lindsey Graham 2%, Bobby Jindal 2%, John Kasich 2%, Rick Perry 1%, Rick Santorum 1%, George Pataki 0%, Jim Gilmore 0%, Someone else 0%, No one 2%, No opinion 4%
NBC/Marist
Margin of error: ± 5.3%

Sample size: 342
July 14–21, 2015Scott Walker
19%
Donald Trump
17%
Jeb Bush
12%
Ben Carson 8%, Mike Huckabee 7%, Rand Paul 5%, Ted Cruz 4%, Marco Rubio 4%, Rick Perry 3%, Chris Christie 2%, John Kasich 2%, Bobby Jindal 1%, Carly Fiorina 1%, Lindsey Graham 1%, Rick Santorum 0%, George Pataki 0%, Jim Gilmore 0%, Undecided 14%
Quinnipiac University
Margin of error: ± 3.8%

Sample size: 666
June 20–29, 2015Scott Walker
18%
Ben Carson
10%
Donald Trump
10%
Ted Cruz 9%, Rand Paul 9%, Jeb Bush 8%, Marco Rubio 7%, Mike Huckabee 5%, Rick Perry 4%, Rick Santorum 4%, Carly Fiorina 3%, Bobby Jindal 3%, John Kasich 2%, Chris Christie 1%, Lindsey Graham 1%, George Pataki 0%, DK/NA 5%
Morning Consult
Margin of error: ± ?%

Sample size: 265
May 31 – June 8, 2015Scott Walker
18%
Jeb Bush
10%
Mike Huckabee
10%
Rand Paul 10%, Marco Rubio 7%, Chris Christie 6%, Ben Carson 5%, Donald Trump 5%, Ted Cruz 4%, Carly Fiorina 2%, Don't know/No opinion/Refused 21%, Someone else 3%
Gravis Marketing
Margin of error: ± 5%

Sample size: 364
May 28–29, 2015Scott Walker
17%
Marco Rubio
13%
Ben Carson
12%
Jeb Bush 10%, Mike Huckabee 8%, Ted Cruz 6%, Rick Santorum 6%, Carly Fiorina 5%, Chris Christie 4%, Rand Paul 4%, Unsure 15%
Des Moines Register
Margin of error: ± 4.9%

Sample size: 402
May 25–29, 2015Scott Walker
17%
Ben Carson
10%
Rand Paul
10%
Jeb Bush 9%, Mike Huckabee 9%, Marco Rubio 6%, Rick Santorum 6%, Ted Cruz 5%, Chris Christie 4%, Donald Trump 4%, Rick Perry 3%, Carly Fiorina 2%, John Kasich 2%, Lindsey Graham 1%, Bobby Jindal 1%, Uncommitted 4%, Not sure 7%
Quinnipiac University
Margin of error: ± 3.8%

Sample size: 667
April 25 – May 4, 2015Scott Walker
21%
Rand Paul
13%
Marco Rubio
13%
Ted Cruz 12%, Mike Huckabee 11%, Ben Carson 7%, Jeb Bush 5%, Chris Christie 3%, Rick Perry 3%, Carly Fiorina 2%, John Kasich 2%, Rick Santorum 2%, Bobby Jindal 1%, Lindsey Graham 0%, Don't know/No answer 6%
Public Policy Polling
Margin of error: ± 4.6%

Sample size: 462
April 23–26, 2015Scott Walker
23%
Marco Rubio
13%
Jeb Bush
12%
Mike Huckabee 10%, Rand Paul 10%, Ted Cruz 8%, Ben Carson 7%, Chris Christie 5%, Rick Perry 4%, Undecided 8%
Loras College
Margin of error: ± 4.3%

Sample size: 509
April 21–23, 2015Scott Walker
12.6%
Marco Rubio
10%
Jeb Bush
9.6%
Mike Huckabee 8.6%, Ted Cruz 6.5%, Ben Carson 6.3%, Rand Paul 6.3%, Chris Christie 5.1%, Rick Santorum 3.5%, Donald Trump 3.1%, Rick Perry 2.6%, Carly Fiorina 1%, Bobby Jindal 1%, John Kasich 1%, Lindsey Graham 0%, Undecided 22.8%
Gravis Marketing
Margin of error: ± 5%

Sample size: 388
April 13, 2015Jeb Bush
16%
Scott Walker
13%
Marco Rubio
12%
Ben Carson 9%, Rand Paul 9%, Mike Huckabee 8%, Ted Cruz 6%, Chris Christie 5%, Carly Fiorina 3%, Rick Santorum 2%, Undecided 17%
Opinion Savvy
Margin of error: ± 4.16%

Sample size: 552
March 20, 2015Scott Walker
29%
Ben Carson
14%
Jeb Bush
12%
Mike Huckabee 11%, Ted Cruz 7%, Chris Christie 5%, Rand Paul 5%, Marco Rubio 5%, Donald Trump 3%, Other/Undecided 10%
Quinnipiac University
Margin of error: ± 3.9%

Sample size: 623
February 16–23, 2015Scott Walker
25%
Rand Paul
13%
Ben Carson
11%
Mike Huckabee 11%, Jeb Bush 10%, Ted Cruz 5%, Marco Rubio 4%, Chris Christie 4%, Rick Santorum 4%, Rick Perry 3%, Bobby Jindal 2%, John Kasich 0%, Unsure 9%
Gravis Marketing
Margin of error: ± 4%

Sample size: 343
February 12–13, 2015Scott Walker
24%
Jeb Bush
10%
Rand Paul
10%
Chris Christie 9%, Mike Huckabee 7%, Marco Rubio 7%, Rick Santorum 6%, Ben Carson 5%, Ted Cruz 4%, Carly Fiorina 3%, Unsure 15%
NBC News/Marist
Margin of error: ± 5.5%

Sample size: 320
February 3–10, 2015Mike Huckabee
17%
Jeb Bush
16%
Scott Walker
15%
Chris Christie 9%, Rand Paul 7%, Ben Carson 6%, Marco Rubio 6%, Rick Santorum 5%, Rick Perry 4%, Ted Cruz 2%, Lindsey Graham 1%, Undecided 14%
Selzer & Co.
Margin of error: ± 4.9%

Sample size: 402
January 26–29, 2015Scott Walker
15%
Rand Paul
14%
Mitt Romney
13%
Mike Huckabee 10%, Ben Carson 9%, Jeb Bush 8%, Ted Cruz 5%, Chris Christie 4%, Rick Santorum 4%, Marco Rubio 3%, Rick Perry 3%, Bobby Jindal 2%, Carly Fiorina 1%, John Kasich 1%, Donald Trump 1%, Mike Pence 0%, Uncommitted 2%, Not sure 5%
Selzer & Co.
Margin of error: ± 4.9%

Sample size: 402
January 26–29, 2015Scott Walker
16%
Rand Paul
15%
Mike Huckabee
13%
Ben Carson 10%, Jeb Bush 9%, Chris Christie 6%, Ted Cruz 6%, Rick Santorum 5%, Marco Rubio 4%, Rick Perry 3%, Bobby Jindal 2%, Carly Fiorina 1%, John Kasich 1%, Donald Trump 1%, Mike Pence 0%, Uncommitted 3%, Not sure 5%
Loras College
Margin of error: ± 5.5%

Sample size: 316
January 21–26, 2015Mitt Romney
13.7%
Mike Huckabee
12.5%
Ben Carson
10.5%
Jeb Bush 9.9%, Scott Walker 8.3%, Rand Paul 6.7%, Ted Cruz 5.1%, Marco Rubio 4.2%, Chris Christie 3.8%, Rick Santorum 3.8%, Rick Perry 2.9%, Bobby Jindal 1.6%, Carly Fiorina 1%, John Kasich 1%, Lindsey Graham 0.3% Undecided 14.7%
Loras College
Margin of error: ± 5.5%

Sample size: 316
January 21–26, 2015Mike Huckabee
14.4%
Jeb Bush
13.1%
Ben Carson
12.8%
Scott Walker 9.9%, Rand Paul 7%, Chris Christie 5.4%, Ted Cruz 5.4%, Marco Rubio 4.2%, Rick Santorum 3.8%, Rick Perry 3.2%, Bobby Jindal 1.6%, Carly Fiorina 1.3%, John Kasich 1.3%, Lindsey Graham 0.6% Undecided 16%
Gravis Marketing
Margin of error: ± 3%

Sample size: 404
January 5–7, 2015Mitt Romney
21%
Jeb Bush
14%
Scott Walker
10%
Mike Huckabee 9%, Rand Paul 8%, Ted Cruz 7%, Chris Christie 5%, Paul Ryan 5%, Marco Rubio 4%, Undecided 18%

Poll sourceDate1st2nd3rdOther
Fox News
Margin of error: ± 5%

Sample size: 329
October 28–30, 2014Mike Huckabee
13%
Ben Carson
12%
Paul Ryan
9%
Jeb Bush 8%, Rand Paul 8%, Chris Christie 7%, Ted Cruz 7%, Rick Santorum 6%, Marco Rubio 5%, Scott Walker 5%, Rick Perry 3%, Bobby Jindal 1%, John Kasich 1%, Rob Portman 0%, Other 1%, None of the above 4%, Don't know 10%
Reuters/Ipsos
Margin of error: ± 4.0%

Sample size: 602
October 23–29, 2014Mitt Romney
17%
Paul Ryan
13%
Chris Christie
12%
Jeb Bush 10%, Scott Walker 10%, Rand Paul 8%, Ted Cruz 7%, Marco Rubio 6%, Rick Santorum 6%, Rick Perry 5%, Wouldn't vote 7%
Selzer & Co.
Margin of error: ± 4.8%

Sample size: 425
October 1–7, 2014Mitt Romney
17%
Ben Carson
11%
Rand Paul
10%
Mike Huckabee 9%, Paul Ryan 8%, Ted Cruz 7%, Rick Perry 7%, Chris Christie 6%, Jeb Bush 4%, Scott Walker 4%, Rick Santorum 3%, Marco Rubio 2%, Bobby Jindal 1%, John Kasich 1%, Mike Pence 0%, Rob Portman 0%, Uncommitted 1%, Not sure 9%
CNN/ORC
Margin of error: ± 5.5%

Sample size: 310
September 8–10, 2014Mike Huckabee
21%
Paul Ryan
12%
Rand Paul
7%
Jeb Bush 6%, Chris Christie 6%, Rick Perry 5%, Marco Rubio 5%, Scott Walker 5%, Ted Cruz 4%, Bobby Jindal 4%, Rick Santorum 3%
Suffolk University
Margin of error: ± 6.83%

Sample size: 206
August 23–26, 2014Mike Huckabee
13.11%
Chris Christie
10.68%
Rick Perry
8.74%
Jeb Bush 7.28%, Rand Paul 6.8%, Paul Ryan 6.31%, Rick Santorum 5.83%, Marco Rubio 5.34%, Ted Cruz 4.85%, Scott Walker 4.37%, Bobby Jindal 2.91%, Jon Huntsman Jr. 0.97%, John Kasich 0.97%, Other 4.37%, Undecided 16.99%, Refused 0.49%
Suffolk University
Margin of error: ± 6.83%

Sample size: 206
August 23–26, 2014Mitt Romney
35.29%
Mike Huckabee
8.82%
Chris Christie
6.47%
Rick Santorum 5.88%, Ted Cruz 5.29%, Rand Paul 5.29%, Jeb Bush 4.71, Rick Perry 4.71%, Paul Ryan 4.12%, Scott Walker 3.53%, Marco Rubio 2.35%, Bobby Jindal 1.76%, Jon Huntsman Jr. 1.18%, John Kasich 0.59%, Undecided 10%
NBC News/Marist
Margin of error: ± 4.1%

Sample size: 558
July 7–13, 2014Jeb Bush
12%
Rand Paul
12%
Paul Ryan
11%
Rick Santorum 9%, Chris Christie 8%, Ted Cruz 7%, Rick Perry 7%, Marco Rubio 7%, Scott Walker 5%, Bobby Jindal 1%, Undecided 20%
Vox Populi Polling
Margin of error: ± 6.6%

Sample size: 222
June 4–5, 2014Jeb Bush
18%
Mike Huckabee
15%
Paul Ryan
13%
Rand Paul 12%, Marco Rubio 11%, Rick Santorum 10%, Ted Cruz 9%, Chris Christie 6%, Scott Walker 6%
Public Policy Polling
Margin of error: ± 5.6%

Sample size: 303
May 15–19, 2014Mike Huckabee
20%
Ted Cruz
15%
Jeb Bush
12%
Rand Paul 10%, Chris Christie 9%, Paul Ryan 8%, Scott Walker 6%, Marco Rubio 4%, Rick Santorum 3%, Someone else/Not sure 13%
The Daily Caller/Vox Populi Polling
Margin of error: ± 8.4%

Sample size: 168
April 22–24, 2014Mike Huckabee
20%
Paul Ryan
19%
Jeb Bush
18%
Ted Cruz 9%, Marco Rubio 9%, Rand Paul 8%, Chris Christie 7%, Scott Walker 6%, Joe Scarborough 4%
Magellan Strategies
Margin of error: ± 5%

Sample size: 330
April 14–15, 2014Jeb Bush
17%
Mike Huckabee
17%
Chris Christie
14%
Rand Paul 11%, Ted Cruz 10%, Scott Walker 8%, John Kasich 5%, Marco Rubio 2%, Undecided 16%
Loras College
Margin of error: ± 4%

Sample size: 600
April 7–8, 2014Mike Huckabee
14.7%
Jeb Bush
10.7%
Rand Paul
8.5%
Paul Ryan 8.3%, Chris Christie 8%, Ted Cruz 6.2%, Marco Rubio 4.7%, Rick Santorum 4.7%, Scott Walker 4.7%, Rick Perry 3%, John Kasich 0.7%, Other 0.7%, Undecided 23.8%
Suffolk University
Margin of error: ± 8.7%

Sample size: 127
April 3–8, 2014Mike Huckabee
11.02%
Jeb Bush
10.24%
Rand Paul
10.24%
Ted Cruz 9.45%, Ben Carson 8.66%, Chris Christie 7.09%, Paul Ryan 6.3%, Sarah Palin 5.51%, Condoleezza Rice 5.51%, Marco Rubio 5.51%, Rick Santorum 5.51%, Scott Walker 5.51%, Bobby Jindal 3.15%, Rick Perry 3.15%, Undecided 3.15%
WPA Research
Margin of error: ± ?

Sample size: 402
March 30, 2014Mike Huckabee
14%
Rand Paul
10%
Scott Walker
8%
Jeb Bush 7%, Ted Cruz 7%, Paul Ryan 7%, Chris Christie 6%, Rick Santorum 5%, Rick Perry 3%, Marco Rubio 3%, Bobby Jindal 2%, Other 2%, Undecided 26%
Public Policy Polling
Margin of error: ± 5.8%

Sample size: 283
February 20–23, 2014Mike Huckabee
17%
Rand Paul
14%
Jeb Bush
13%
Chris Christie 10%, Ted Cruz 10%, Paul Ryan 9%, Bobby Jindal 7%, Scott Walker 7%, Marco Rubio 3%, Other/Undecided 11%

Poll sourceDate1st2nd3rdOther
Cygnal
Margin of error: ± 2.37%

Sample size: 1,705
July 10–12, 2013Marco Rubio
11.4%
Rand Paul
10.5%
Paul Ryan
9.3%
Jeb Bush 8.7%, Chris Christie 7.7%, Rick Santorum 6.7%, Ted Cruz 6.1%, Scott Walker 2.1%, Bobby Jindal 1.3%, Undecided 36.3%
Public Policy Polling
Margin of error: ± 6.2%

Sample size: 250
July 5–7, 2013Rand Paul
18%
Chris Christie
16%
Paul Ryan
15%
Jeb Bush 14%, Marco Rubio 11%, Ted Cruz 10%, Rick Santorum 6%, Bobby Jindal 2%, Susana Martinez 1%, Other/Undecided 7%
Public Policy Polling
Margin of error: ± 5.4%

Sample size: 326
Feb. 1–3, 2013Mike Huckabee
16%
Marco Rubio
16%
Rand Paul
15%
Jeb Bush 14%, Chris Christie 12%, Paul Ryan 10%, Susana Martinez 4%, Bobby Jindal 3%, Rick Perry 3%, Someone Else/Undecided 7%
Public Policy Polling
Margin of error: 5.1%

Sample size: 363
July 12–15, 2012Rick Santorum
17%
Mike Huckabee
17%
Chris Christie
16%
Rand Paul 11%, Marco Rubio 10%, Jeb Bush 8%, Paul Ryan 6%, Sarah Palin 4%, Scott Walker 4%, Someone else/Not sure 8%
Public Policy Polling
Margin of error: 5.3%

Sample size: 346
May 3–5, 2012Rick Santorum
16%
Mike Huckabee
16%
Chris Christie
15%
Jeb Bush 10%, Sarah Palin 10%, Rand Paul 9%, Marco Rubio 7%, Paul Ryan 5% Someone else/Not sure 10%

Aftermath and controversy

The caucus results led to immediate controversy when Ben Carson accused Cruz's campaign of employing dishonest tactics, specifically claiming that Cruz supporters falsely told caucus-goers that Carson had dropped out to convince them to switch their votes.
Trump subsequently accused Cruz of "stealing" the Iowa caucuses through fraud, taking to social media to demand that Cruz be disqualified and the election results invalidated. These accusations foreshadowed continued tensions between Cruz and Trump as the primary campaign progressed. According to an interview of Trump with Greta Van Susteren of On the Record, he said, “Everything about it was disgraceful. It was a fraud as far as I was concerned.”
The results also had an immediate impact on the Republican field, as Rand Paul, Mike Huckabee, and Rick Santorum suspended their campaigns in the days following the caucuses.

Geographic and demographic analysis

Exit polling revealed Cruz's victory was built on strong support from evangelical voters, who comprised 62% of caucus participants. He won 33% of evangelical voters, while also performing strongly in rural counties and areas with high evangelical populations.
Trump's support was notably stronger in eastern Iowa and working-class areas, particularly along the Mississippi River. He performed best among first-time caucus participants and voters without college degrees. Rubio showed particular strength in suburban areas around Des Moines, Cedar Rapids, and other population centers, winning 28% of college graduates and performing well among late-deciding voters.