We have fallen into a relatively dry spell for polling in the race between Sen. Patty Murray (D-WA) and real estate salesman Dino Rossi (R). Rasmussen has now released their latest Washington state poll showing Rossi leading Murray 48% to 47%. The poll of 750 likely voters was taken on Tuesday and has a margin of error of 4%.

This poll breaks Murray’s streak of eight consecutive polls with the lead. Before today’s release, the most recently taken poll was also by Rasmussen (17th Oct), and showed Murray with a +3% lead over Rossi (49% to 46%).

Using my usual Monte Carlo analysis employing 1,000,000 simulated elections, we find from the newest Rasmussen poll that Murray wins 415,950 elections to Rossi’s 573,763 wins. Thus, evidence from this poll alone suggests that, if the election had been held last Tuesday, Rossi would have a 58% probability of beating Murray to Murray’s 42% probability of beating Rossi. Given that the winning probability is under 95%, a statistician would tell us that the results suggest a statistical tie. Here is the distribution of simulated election outcomes:

A more comprehensive picture of the election emerges by combining all polls from the past two weeks. Besides the two Rasmussen polls already mentioned, we include the Marist poll taken from 14-17 October on 589 likely voters, giving Murray a +1% lead and a Public Policy Polling poll taken from 14-16 October on 1,873 likely voters and gave Murray a +2% lead. (Other polls in this race started the survey prior to the 14th of October so aren’t included.)

The combined meta-poll has 3,962 “votes” of which 1,920 go to Murray (48.5%), 1,862 go to Rossi (47.0%), and 180 (4.5%) just go away. In the Monte Carlo analysis, Murray wins 746,418 times and Rossi wins 249,788 times. In other words, the four polls suggest that Murray would win an election held over the past two weeks with a probability of 74.9%, and Rossi would win with a probability of 25.1%.

This collection of four recent polls gives the appearance that the race has tightened up a bit (compare this to the 98% win probability for Murray from pooled polls early last week). Keep in mind, however, that three of the four most recent polls are robopolls. As I discussed previously, there is a strong trend of robopolls showing Murray under performing relative to live-interview polls. Perhaps we will get a live-interview poll tomorrow….

It’s the Tuesday before the election. And that make for an excellent excuse to enjoy an evening of politics under the influence. Please join us at the Seattle chapter of Drinking Liberally at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Some of us will be there early for dinner.

Not in Seattle? There is a good chance you live near one of the 250 other chapters of Drinking Liberally.

On my way home this evening, I came across a pick-up truck parked on the street in Redmond, towing this trailer:

Without even thinking about, I started glancing around for evidence of a Dino Rossi campaign event….

(And there are almost 50 more links to media clips from the past week in politics at Hominid Views.)

This poll from Marist makes eight consecutive polls in which Sen. Patty Murray (D-WA) has the lead over Dino Rossi (R), even if her 48% to 47% lead is smallish.

I do a more detailed analysis of the poll, and an analysis using all nine October polls, at Hominid Views.

Man, after all this number crunching and writing…I needs me a drink!

It’s Tuesday following the ballot drop…making it a great opportunity to enjoy and evening of politics under the influence. Please join us at the Seattle chapter of Drinking Liberally at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Stop by earlier for dinner.

Not in Seattle? There is a good chance you live near one of the 249 other chapters of Drinking Liberally.

Washington state voters are, seemingly, under a polling blitzkrieg. Today another poll is released in the race between Sen. Patty Murray (D) and real estate salesman turned foreclosure opportunity seminar motivational speaker Dino Rossi (R).

This poll comes from Public Policy Polling (PPP) and shows Murray leading Rossi 49% to 47%. The poll was taken from 14th to the 16th of October on a sample of 1,873 likely Washington voters. The margin of error is 2.3%.

PPP makes an interesting observation about the race (emphasis added):

There’s a pretty strong argument that the Washington Senate race is the most stable in the country: PPP finds Patty Murray leading Dino Rossi 49-47, basically identical to our July poll of the race that found her ahead 49-46.

The reason for the stability is that voters know these candidates, they know what they think of them, and nothing they’ve heard during this campaign has changed those opinions in one direction or the other. In July Murray’s approval rating was 46/45. Now it’s 47/48. In July Rossi’s favorability was 43/48. Now it’s 44/49.

Compare this with yesterday’s Rasmussen lede (emphasis added):

Democratic incumbent Patty Murray is barely ahead of Republican challenger Dino Rossi now as the lead seesaws again in Washington’s neck-and-neck U.S. Senate race.

The fact is, Murray has now led in the last seven of the eight polls taken in October with margins from +1 to +13 and with an (unweighted) average of just over +5%. Take a look at the entire polling history:

Note to pollsters and reporters…that meme about how close and back-and-forth this race is? Yeah…that last’s month meme based on a tiny blip in the data.

Note: The graph in the first version of this post included a poll by DSCC. I’ve reposted the graph without that poll.

Update: At Hominid Views I do some statistical analysis of the poll and further examine the differences between robopolls and live-interview polls in this race.

(And there are links to some 50 more clips from the past week in politics at Hominid Views.)

I posted the results earlier today of the Washington Senate race based on KPLU’s news reports. At noon today, the KCTS/KPLU/Washington Poll top lines were released for public consumption.

In that all-important race between the single most powerful mom-in-tennis-shoe in the Senate & nation, Sen. Patty Murray (D-WA), and the single most sought-after motivational speaker on the foreclosure profiteering seminar circuit, Dino Rossi (R), we find Sen. Murray leading 50% to 42%. This makes five polls in a row that has Murray in the lead.

This poll surveyed 500 people from October 5th to the 14th. Hence, it overlaps every one of the other five October polls. Here is summary of all the polls this month:

	Start	End	Samp.		%	%	%
Poll	date	date	size	MOE	Murray	Rossi	Diff
WA Poll	05-Oct	14-Oct	500	4.3	50	42	D+8
SurveyUSA	11-Oct	14-Oct	606	4.1	50	47	D+3
CNN/Time/OR	08-Oct	12-Oct	850	3.5	51	43	D+8
Elway	07-Oct	11-Oct	450	4.6	51	38	D+13
Fox	09-Oct	09-Oct	1000	3.0	47	46	D+1
Rasmussen	06-Oct	06-Oct	750	4.0	46	49	R+3

What does this poll tell us by itself? A Monte Carlo analysis using the observed sample size and percentages gives Murray 902,830 wins to Rossi’s 92,001 out of a million simulated elections. That is, the poll provides evidence that Murray would have a 90.8% probability of beating Rossi in an election held now.

But we can pool the results from all six of the polls shown in the table. This gives us a total of 4,156 “votes”, of which 3,890 of them go to either Rossi or Murray. Murray gets 48.9% to Rossi’s 44.7% (or, if we look at just the votes for Murray and Rossi, Murray is up 52.2% to 47.8%). A simulation analysis finds Murray beating Rossi with 975,049 wins to his 24,332 wins.

The new KCTS/KPLU/Washington Poll has added a bit more certainty to Murray’s lead. Yesterday, this same analysis using all but today’s poll gave Murray a 94.5% chance of winning. Today, with six polls, we find that Murray would have a 97.6% chance of beating Rossi in an election right now.

Finally, let me address a meme about this race that has been quite prevalent in the recent media. There is an idea the the polls are “all over the place.” Maybe. But not really. Let’s look at results of polls taken in September and October:

Since these polls are taken on a sample of the underlying voting population, there is some uncertainty about the results. The vertical bars on the poll results show the plausible range that the voting population could have, given the margin of error inherent in the poll. (Other problems can lead to biased estimates; the margin of error only incorporates uncertainty reflecting the size of the sample.) And even then, by chance, we expect the true value to lie outside of the plausible range in about one in twenty polls.

Looking at the recent polls, it seems the last five polls mostly overlap, suggesting that the truth lies somewhere near a 54% Murray, 46% Rossi result. We also see this in early September. From mid-September to early October, Murray appears to do significantly worse.

Remember the discussion with the Elway poll last Tuesday? Elway was compelled to justify his noticeably higher numbers for Murray, and suggested that there was a difference between robopolls and live-interview polls. (Of course, if we consider the plausible range, the Elway poll fits right in.) The polls released since Tuesday support Elway’s suggestion.

Elway did not offer a hypothesis why robopolls would turn in different results than the live-interview polls, but I did. Via Goldy:

As Darryl suggested the other night at Drinking Liberally, what if the enthusiasm gap we’ve all been hearing about is largely manifested in who is or is not willing to give up ten minutes to interact with an automated poll? I know I’ve hung up on a couple robo-polls this year, but find it harder to do so with a real live person. Interesting hypothesis.

This looks right for all the recent polling. We see that the three live-interview polls (Elway, WA poll, and CNN) all post numbers on the high side and the robopolls (SUSA, Rasmussen and FOX News) all come in on the low side. That big dip in the middle is formed from six robopolls taken in a row. In fact, Rasmussen and FAUX News both use the same company—Pulse Opinion Research–to do their polling. It may not be chance that FOX New and Rasmussen both give Murray her worse performance in this series. And this would explain the question I posed in August, “What the hell happened to Survey USA?”

The robopoll/live interview/enthusiasm gap hypothesis was offered Tuesday before the three most recent polls were released, and I am now pretty confident that this is what is happening in the Murray—Rossi race here in Washington.

I am less confident about other House and Senate races nationally, but if it can happen here, it might well be happening elsewhere. I think there is a fair possibility that robopolls will systematically underestimate the performance of Democrats nationwide, which will make for a pretty darned interesting election night!

(Cross posted at Hominid Views.)

KPLU is reporting that a new poll in the Washington senatorial race will be released today from The Washington Poll. The poll shows Sen. Patty Murray (D) leading real estate opportunist cum foreclosure seminar motivational speaker Dino Rossi (R) by 50% to 42%.

The sample size is 500 giving a margin of error of 4.3%. I’ll provide a more detailed analysis when the poll results are released.

The Washington poll is made using live calls (like Elway). This poll differs from most other polls in this race in that the results are of registered voters, rather than likely voters. The poll was sponsored by KPLU and KCTS-9 and conducted by the University of Washington out of the Political Science Department. (In the interest of full disclosure, I work for the UW; however, I have nothing to do with this poll.)

Yesterday I alluded to a new Survey USA poll that I thought would be released in a day or two for the Senate race between Sen. Patty Murray (D) and foreclosure seminar motivational speaker Dino Rossi (R). Well…it happened today.

The new poll has Murray leading Rossi, 50% to 47% from a survey of 606 likely voters taken from 22 October to 14 October. The margin of error is 4.1%.

This is the fourth poll in a row that has Murray leading Rossi. In fact, over the past month, there have been nine polls in this race (not including those released by the candidates or political parties). Murray has led in seven of the nine polls. Yeah…Rossi has a pair, but they are really pretty tiny (+1 and +3) compared to Murray’s (+3, +7, +13, +1, +1, +2, +5).

A Monte Carlo analysis of the SurveyUSA poll gives Murray 699,651 out of a million simulated elections. Rossi wins 290,266 times. In other words, in an election held now, Murray would have a 70.7% chance of beating Rossi, given the evidence offered in this poll. Here is the distribution of simulated election outcomes:

We now have five polls taken in October (the earliest poll was from Oct 6). Let throw them together for a better picture of the evidence. The five polls yield 3,656 “votes” of which 3,430 are for one of the candidates. Murray gets 1,781 “votes” (48.7%) and Rossi, 1,649 (45.1%). From the simulated elections, Murray wins 943,548 times; Rossi wins 55,016 times. Thus, the October polls, taken as a whole, support the idea that Murray would win with a 94.5% probability in an election held now. Here is the picture:

I’ve now written about new polls in this race for five days straight. If tomorrow bring us another poll then we can declare it WAPollpalooza week. And then maybe I can get some rest on the seventh day….

Yesterday we had a new Elway poll in the senatorial race between Sen. Patty Murray (D) and real estate opportunist Dino Rossi (R).

Today there is a new CNN/Time/Opinion Research poll weighing in on the race. The poll of 850 likely voters, taken from October 8 through 10, has Murray leading Rossi 51% to 43%. The margin of error is 3.5%. This result is pretty similar to yesterday’s Elway poll.

A Monte Carlo analysis consisting of a million simulated elections at the observed preferences in this new poll has Murray winning 954,664 times and Rossi winning 42,982 times. The evidence from this latest poll suggests that, in an election held today, Murray would win with a 95.7% probability; Rossi with a 4.3% probability. Here is the distribution of outcomes from the simulated elections:

But I missed another poll that was released on Monday or Tuesday. A FOX News poll taken on 9 Oct on a sample of 1000 individuals found Murray with a 47% to 46% lead over Rossi (3% margin of error). Thus, there have been a total of four polls published in October and Murray has led in the last three—Rossi last led in a 6 Oct Rasmussen poll.

Given that all four of these polls were taken either consecutively or over overlapping days, we can combine them for a better picture of how this race is shaping up over the the second week of October. The four October polls give a total of 3,050 responses, of which 2,842 went to either Murray or Rossi. Murray got 1,478 ( 48.5%) and Rossi got 1364 ( 44.7%). A Monte Carlo analysis gives Murray 934,835 wins to Rossi’s 63,503 wins.

Thus, the four polls combined provide evidence that an election held over the past week would go Murray’s way with a 93.6% probability, and would go Rossi’s way with a 6.4% probability:

A look at the polling to date suggests that Murray’s September slump has ended; she has clearly retaken the lead and it seems to be her strongest lead to date.

This is definitely a good position for Murray to be in during the week that ballots drop. The next couple of polls will be telling, and I think we’ll have new polls from Survey USA and the Washington Poll within a few days, so stay tuned….

(Cross posted at Hominid Views.)

As is our custom, Tuesday brings us together for an evening of politics under the influence. Please join us at the Seattle chapter of Drinking Liberally at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Stop by earlier for dinner.

Not in Seattle? There is a good chance you live near one of the 249 other chapters of Drinking Liberally.

A new Elway poll has just been released for Washington state. Included in the poll is a head-to-head match-up in the Washington state senatorial race between Sen. Patty Murray and real estate salesman Dino Rossi. The poll was conducted using live interviews between October 7 and October 11 on a sample of 450 likely voters. The margin of error is 4.6%.

The results have Murray leading Rossi by 51% to 38% with “leaners” excluded. Murray does even better (55% to 40%) if “leaners” are included. I’ll stick with the former numbers in what follows. Here is the polling in this race to date (excluding polls released by the campaigns):

This new poll reverses a not-so-good trend for Murray over the past month. Her lead had the appearance of slipping away (although really the recent polls have all been a statistical tie).

You may also notice that all four of the Elway polls are more favorable for Murray than nearly all other polls. As Goldy mentions, Elway goes to some effort to explain this discrepancy. Elway shows that there are distinctly different trends for polls done using automated questions compared to live interviews. The robopolls showed Rossi with a slight lead early in the year with the trend lines converging to a tie right now. The live polls showed Rossi and Murray tied early on, with Rossi staying relatively flat and Murray pulling away by about 7 points. No explanation is offered, but the implication is that Elway’s live polls are more accurate.

We can, to some extent, evaluate Elway’s hypothesis. Here is a graph I published on Nov 3, 2008, when Dino Rossi was running against Gov. Christine Gregoire in the Washington state Gubernatorial race:

Here again, Elway seemed to favor Rossi’s opponent relative to other polls, suggesting Murray would win 51% to 39%. The Washington Poll, another live interview poll, was also on the high side relative to other polls earlier (51.4% to 45%) and close later (50% to 48%). In the last month most pollsters had the race within two points: Strategic Vision (50% to 48% and 49% to 47% earlier), Rasmussen (50% to 48%), and SurveyUSA (50% to 48% and 48% to 47% earlier). The day after this graph was made, SurveyUSA released their final poll (52% to 46%).

The final tally in the Gregoire–Rossi race was 53.2% to 46.8% (+6.4). SurveyUSA’s last poll nailed it (+6), and the Washington Poll got the spread right (+6) in their earlier poll. Elway underestimated both candidates’ percentages and had a high spread (+12). This suggests that most of the recent polls underestimate Murray’s performance, even if the Elway poll probably overestimates it.

Back to the Elway poll…As usual, I’ll analyze it using simulated elections of 450 likely voters voting at the observed percentages in order to make a probability statement about who would win in a hypothetical election held now. From a million such simulated elections, we find that Murray wins 979,930 times and a Senator Rossi happens 18,537 times. In other words, this poll gives Murray 98.1% chance of winning an election right now. Rossi’s probability is 1.9%. Here is the distribution of outcomes from the simulated elections:

Compare today’s picture to that from last Friday’s Rasmussen poll. In fact, since the Rasmussen poll was conducted on October 6 on a sample of 750 likely voters. It showed Rossi leading Murray 49% to 46%. Given that the Rasmussen poll was taken the day before the Elway poll started, it seems reasonable to combine ’em.

The combined Elway-Rasmussen poll sampled 1,200 likely voters of which 1113 chose one or the other candidate. Murray got 574 votes (47.8%), and Rossi got 538 (44.8%). A Monte Carlo analysis using a million simulated elections gave Murray 772,311 wins to Rossi’s 221,338 wins. In other words, these two polls combined suggests that Murray would have a 77.7% of beating Rossi if the election was held now.

To summarize, in combining the only two October polls to date—one done with live calls one by robocalls—Murray still comes out ahead, albeit not with a statistically significant lead.