Races · Senate · 2016 · IA

Senate · class II · open seat

Patty Judge vs Chuck Grassley

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Lean R — · 40 polls · 0 markets Last poll 3471d ago Rating 1d ago

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Editorial raters moved while polling has gone quiet

The last rating change here was 1d ago, but only 40 polls have landed in the last 60 days. When raters move and pollsters don't, the rating shift may be running ahead of the data. Watch for a late-cycle correction in either direction.

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Polling average

Simple Weighted House-corrected Trimmed LOESS Kalman

Method:Weighted, plus each pollster's measured bias subtracted before averaging.

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All polls · 40 results

Pollster:Population:Lean:High-quality only (weight ≥ 1.5)Sort:40 of 40 polls

End	Pollster	Weight	Lean	Sample	MoE	Pop	Trust signals	Results	Source
11/7/2016	SurveyMonkey	1.00	—(D+6.1)	1781	±4.6	unknown	historical bias D+6.1pt3471d old+2 historical bias D+6.1pt Across 236 historical scored polls the average error vs. actual margin is D+6.1pt — a measurable house effect. 3471d old Poll was fielded 3471 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. high variance vs editorial consensus Stdev of (poll − rater consensus) across 236 historical paired polls exceeds 8pt — this pollster's results swing widely relative to where the editors place the same races. n=1,781 Sample size of 1,781 respondents implies a margin of error around ±2.3pt — tighter than the ~600-respondent typical.	Chuck Grassley 57.0 · Patty Judge 39.0	poll arch
11/4/2016	Des Moines Register/Selzer	1.00	—	800	±3.5	unknown	no scored polls3474d old no scored polls Pollster has no historical polls with a known outcome in our database, so accuracy and bias cannot be measured. 3474d old Poll was fielded 3474 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average.	Chuck Grassley 56.0 · Patty Judge 33.0	poll arch
11/3/2016	Emerson College	1.00	—(D+0.7)	700	±3.6	unknown	3475d oldtracks editorial consensus+1 3475d old Poll was fielded 3475 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 234 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom. accurate · bias D+0.7pt Across 117 historical scored polls this pollster's average error vs. actual margin is D+0.7pt — within ±1pt.	Chuck Grassley 60.0 · Patty Judge 32.0	poll arch
11/3/2016	Loras College	0.74	—(D+1.9)	500	±4.4	unknown	4 scored polls3475d old 4 scored polls Pollster has only 4 historical polls with a known outcome to score against — too few for stable accuracy estimates. 3475d old Poll was fielded 3475 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average.	Chuck Grassley 53.0 · Patty Judge 37.0	poll arch
10/31/2016	SurveyMonkey	1.00	—(D+6.1)	984	±4.6	unknown	historical bias D+6.1pt3478d old+1 historical bias D+6.1pt Across 236 historical scored polls the average error vs. actual margin is D+6.1pt — a measurable house effect. 3478d old Poll was fielded 3478 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. high variance vs editorial consensus Stdev of (poll − rater consensus) across 236 historical paired polls exceeds 8pt — this pollster's results swing widely relative to where the editors place the same races.	Chuck Grassley 56.0 · Patty Judge 41.0	poll arch
10/26/2016	Quinnipiac University	1.00	—(D+1.9)	791	±3.5	unknown	3483d oldtracks editorial consensus 3483d old Poll was fielded 3483 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 81 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 56.0 · Patty Judge 38.0	poll arch
10/16/2016	Washington Post/SurveyMonkey	1.00	—	1135	±0.5	unknown	no scored polls3493d old+1 no scored polls Pollster has no historical polls with a known outcome in our database, so accuracy and bias cannot be measured. 3493d old Poll was fielded 3493 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. D+5.0pt vs editors Across 12 historical polls where ≥2 editorial raters had rated the race (Cook / Sabato / IE / 538 / DDHQ etc.), this pollster's D-margin averaged 5.0pt MORE D-favorable than the rater consensus. Systematic D-lean relative to conventional wisdom.	Chuck Grassley 56.0 · Patty Judge 40.0	poll arch
10/14/2016	Google Consumer Surveys	0.33	—(R+12.2)	523	±4.2	unknown	weight 0.333 scored polls+2 weight 0.33 Aggregation weight is 0.33 (1.0 ≈ average). Weight combines historical accuracy, methodology, and recency. 3 scored polls Pollster has only 3 historical polls with a known outcome to score against — too few for stable accuracy estimates. 3495d old Poll was fielded 3495 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. high variance vs editorial consensus Stdev of (poll − rater consensus) across 6 historical paired polls exceeds 8pt — this pollster's results swing widely relative to where the editors place the same races.	Chuck Grassley 56.0 · Patty Judge 41.0	poll arch
10/10/2016	The Times-Picayune/Lucid	1.01	L(D+4.0)	917	±3.0	unknown	3499d old 3499d old Poll was fielded 3499 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average.	Chuck Grassley 51.0 · Patty Judge 39.0	poll arch
10/6/2016	Des Moines Register/Selzer	1.00	—	642	±3.5	unknown	no scored polls3503d old no scored polls Pollster has no historical polls with a known outcome in our database, so accuracy and bias cannot be measured. 3503d old Poll was fielded 3503 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average.	Chuck Grassley 53.0 · Patty Judge 36.0	poll arch
9/22/2016	Loras College	0.74	—(D+1.9)	491	±4.4	unknown	4 scored polls3517d old 4 scored polls Pollster has only 4 historical polls with a known outcome to score against — too few for stable accuracy estimates. 3517d old Poll was fielded 3517 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average.	Chuck Grassley 54.0 · Patty Judge 37.0	poll arch
9/21/2016	Quinnipiac University	1.00	—(D+1.9)	612	±4.0	unknown	3518d oldtracks editorial consensus 3518d old Poll was fielded 3518 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 81 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 55.0 · Patty Judge 43.0	poll arch
9/14/2016	Monmouth University	1.00	—(D+5.0)	404	±4.9	unknown	historical bias D+5.0pt3525d old+1 historical bias D+5.0pt Across 19 historical scored polls the average error vs. actual margin is D+5.0pt — a measurable house effect. 3525d old Poll was fielded 3525 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 30 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 56.0 · Patty Judge 39.0	poll arch
9/8/2016	RABA Research	1.00	—	1054	±3.0	unknown	no scored polls3531d old no scored polls Pollster has no historical polls with a known outcome in our database, so accuracy and bias cannot be measured. 3531d old Poll was fielded 3531 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average.	Chuck Grassley 50.0 · Patty Judge 37.0	poll arch
8/31/2016	Public Policy Polling	1.00	—(D+1.1)	827	±3.4	unknown	3539d olduncorrelated with editorial consensus+1 3539d old Poll was fielded 3539 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 49.0 · Patty Judge 43.0	poll arch
8/19/2016	CBS News/YouGov	0.92	L(D+3.4)	987	±4.0	unknown	historical bias D+3.4pt3551d old+1 historical bias D+3.4pt Across 16 historical scored polls the average error vs. actual margin is D+3.4pt — a measurable house effect. 3551d old Poll was fielded 3551 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 23 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 45.0 · Patty Judge 38.0	poll arch
8/16/2016	Quinnipiac University	1.00	—(D+1.9)	846	±3.4	unknown	3554d oldtracks editorial consensus 3554d old Poll was fielded 3554 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 81 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 51.0 · Patty Judge 42.0	poll arch
8/10/2016	Suffolk University	1.44	neutral(D+0.1)	500	±4.4	unknown	3560d oldbias D+0.1pt+1 3560d old Poll was fielded 3560 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. bias D+0.1pt Across 15 historical scored polls the average error vs. actual margin is D+0.1pt. tracks editorial consensus Across 55 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 52.0 · Patty Judge 42.0	poll arch
8/7/2016	NBC/WSJ/Marist	1.20	neutral(R+0.7)	899	±3.3	unknown	3563d oldbias R+0.7pt+1 3563d old Poll was fielded 3563 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. bias R+0.7pt Across 13 historical scored polls the average error vs. actual margin is R+0.7pt. tracks editorial consensus Across 16 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 52.0 · Patty Judge 42.0	poll arch
7/15/2016	CBS News/YouGov	0.92	L(D+3.4)	998	±4.8	unknown	historical bias D+3.4pt3586d old+1 historical bias D+3.4pt Across 16 historical scored polls the average error vs. actual margin is D+3.4pt — a measurable house effect. 3586d old Poll was fielded 3586 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 23 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 45.0 · Patty Judge 37.0	poll arch
7/11/2016	Monmouth University	1.00	—(D+5.0)	401	±4.9	unknown	historical bias D+5.0pt3590d old+1 historical bias D+5.0pt Across 19 historical scored polls the average error vs. actual margin is D+5.0pt — a measurable house effect. 3590d old Poll was fielded 3590 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. tracks editorial consensus Across 30 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 52.0 · Patty Judge 42.0	poll arch
7/10/2016	NBC/WSJ/Marist	1.20	neutral(R+0.7)	822	±3.4	unknown	3591d oldbias R+0.7pt+1 3591d old Poll was fielded 3591 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. bias R+0.7pt Across 13 historical scored polls the average error vs. actual margin is R+0.7pt. tracks editorial consensus Across 16 historical paired polls, this pollster's D-margins track the rater consensus (Cook / Sabato / IE / 538 / DDHQ etc.) with high correlation (r ≥ 0.85) and small mean delta (\|Δ\| ≤ 2pt). Their results align with conventional wisdom.	Chuck Grassley 52.0 · Patty Judge 42.0	poll arch
6/28/2016	Loras College	0.74	—(D+1.9)	600	±4.0	unknown	4 scored polls3603d old 4 scored polls Pollster has only 4 historical polls with a known outcome to score against — too few for stable accuracy estimates. 3603d old Poll was fielded 3603 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average.	Chuck Grassley 46.0 · Patty Judge 45.0	poll arch
6/23/2016	Public Policy Polling	1.00	—(D+1.1)	897	±3.3	unknown	3608d olduncorrelated with editorial consensus+1 3608d old Poll was fielded 3608 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 46.0 · Patty Judge 39.0	poll arch
6/13/2016	Public Policy Polling	1.00	—(D+1.1)	630	±3.9	unknown	3618d olduncorrelated with editorial consensus+1 3618d old Poll was fielded 3618 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 48.0 · Patty Judge 41.0	poll arch
1/10/2016	Public Policy Polling	1.00	—(D+1.1)	1901	±2.3	unknown	3773d olduncorrelated with editorial consensus+2 3773d old Poll was fielded 3773 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,901 Sample size of 1,901 respondents implies a margin of error around ±2.2pt — tighter than the ~600-respondent typical.	Chuck Grassley 52.0 · Rob Hogg 28.0	poll arch
1/10/2016	Public Policy Polling	1.00	—(D+1.1)	1901	±2.3	unknown	3773d olduncorrelated with editorial consensus+2 3773d old Poll was fielded 3773 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,901 Sample size of 1,901 respondents implies a margin of error around ±2.2pt — tighter than the ~600-respondent typical.	Chuck Grassley 53.0 · Tom Fiegen 29.0	poll arch
1/10/2016	Public Policy Polling	1.00	—(D+1.1)	1901	±2.3	unknown	3773d olduncorrelated with editorial consensus+2 3773d old Poll was fielded 3773 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,901 Sample size of 1,901 respondents implies a margin of error around ±2.2pt — tighter than the ~600-respondent typical.	Chuck Grassley 52.0 · Bob Krause 28.0	poll arch
12/13/2015	Public Policy Polling	1.00	—(D+1.1)	1426	±2.6	unknown	3801d olduncorrelated with editorial consensus+1 3801d old Poll was fielded 3801 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 54.0 · Rob Hogg 29.0	poll arch
12/13/2015	Public Policy Polling	1.00	—(D+1.1)	1426	±2.6	unknown	3801d olduncorrelated with editorial consensus+1 3801d old Poll was fielded 3801 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 54.0 · Tom Fiegen 29.0	poll arch
12/13/2015	Public Policy Polling	1.00	—(D+1.1)	1426	±2.6	unknown	3801d olduncorrelated with editorial consensus+1 3801d old Poll was fielded 3801 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 53.0 · Bob Krause 28.0	poll arch
11/1/2015	Public Policy Polling	1.00	—(D+1.1)	1668	±2.4	unknown	3843d olduncorrelated with editorial consensus+2 3843d old Poll was fielded 3843 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,668 Sample size of 1,668 respondents implies a margin of error around ±2.4pt — tighter than the ~600-respondent typical.	Chuck Grassley 53.0 · Rob Hogg 29.0	poll arch
11/1/2015	Public Policy Polling	1.00	—(D+1.1)	1668	±2.4	unknown	3843d olduncorrelated with editorial consensus+2 3843d old Poll was fielded 3843 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,668 Sample size of 1,668 respondents implies a margin of error around ±2.4pt — tighter than the ~600-respondent typical.	Chuck Grassley 54.0 · Tom Fiegen 30.0	poll arch
11/1/2015	Public Policy Polling	1.00	—(D+1.1)	1668	±2.4	unknown	3843d olduncorrelated with editorial consensus+2 3843d old Poll was fielded 3843 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,668 Sample size of 1,668 respondents implies a margin of error around ±2.4pt — tighter than the ~600-respondent typical.	Chuck Grassley 52.0 · Bob Krause 28.0	poll arch
8/9/2015	Public Policy Polling	1.00	—(D+1.1)	1500	±2.5	unknown	3927d olduncorrelated with editorial consensus+2 3927d old Poll was fielded 3927 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,500 Sample size of 1,500 respondents implies a margin of error around ±2.5pt — tighter than the ~600-respondent typical.	Chuck Grassley 52.0 · Rob Hogg 28.0	poll arch
8/9/2015	Public Policy Polling	1.00	—(D+1.1)	1500	±2.5	unknown	3927d olduncorrelated with editorial consensus+2 3927d old Poll was fielded 3927 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,500 Sample size of 1,500 respondents implies a margin of error around ±2.5pt — tighter than the ~600-respondent typical.	Chuck Grassley 53.0 · Tom Fiegen 30.0	poll arch
8/9/2015	Public Policy Polling	1.00	—(D+1.1)	1500	±2.5	unknown	3927d olduncorrelated with editorial consensus+2 3927d old Poll was fielded 3927 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt. n=1,500 Sample size of 1,500 respondents implies a margin of error around ±2.5pt — tighter than the ~600-respondent typical.	Chuck Grassley 51.0 · Bob Krause 29.0	poll arch
9/28/2014	Public Policy Polling	1.00	—(D+1.1)	1192	±2.8	unknown	4242d olduncorrelated with editorial consensus+1 4242d old Poll was fielded 4242 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 51.0 · Tom Vilsack 42.0	poll arch
5/19/2014	Public Policy Polling	1.00	—(D+1.1)	914	±3.3	unknown	4374d olduncorrelated with editorial consensus+1 4374d old Poll was fielded 4374 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 49.0 · Tom Vilsack 39.0	poll arch
2/23/2014	Public Policy Polling	1.00	—(D+1.1)	869	±3.3	unknown	4459d olduncorrelated with editorial consensus+1 4459d old Poll was fielded 4459 days ago. Older polls reflect an earlier state of the race and are weighted down in the rolling average. uncorrelated with editorial consensus Across 368 historical paired polls, this pollster's margins don't track the editorial consensus (Pearson r < 0.5). Independence from consensus is informational — could indicate genuine methodological independence or noisy results. bias D+1.1pt Across 72 historical scored polls the average error vs. actual margin is D+1.1pt.	Chuck Grassley 48.0 · Tom Vilsack 41.0	poll arch

Trust signals are deterministic flags computed from the pollster scorecard (track-record size, historical bias, aggregation weight) and the poll itself (sample size, population, age, citation availability). No interpretation; click any row to see the cited numbers behind each flag.

Editorial ratings · poll-vs-rater

3 raters

Rater	Rating	Updated	Poll D-marg.	Rater marg.	Δ poll−rater
The Cook Political Report	Likely R	Nov 2	—	-9.0	—
Real Clear Politics	Safe R	Nov 7	—	-18.0	—
Sabato's Crystal Ball	Safe R	Nov 7	—	-18.0	—

Δ POLL−RATER = polling-consensus margin minus the rater's implied bucket midpoint. Positive = polls more D than rater; negative = rater more D than polls. |Δ| < 0.6 well-aligned · 0.6–1.5 mild divergence · ≥1.5 contested call.

last poll 116 months ago (11/7/2016) last market quote — rating computed 1 day ago

Rating history (1 change)

5/6/2026 Lean R via pvi