As I briefly mentioned earlier today, we got a new Rasmussen Poll in the race between Sen. Patty Murray (D) and Dino Rossi (R). The poll shows Murray leading Rossi 51% to 46%. The poll surveyed 750 likely voters on the 14th of September.

With this new poll, we have now had seven polls taken (and released to the public) over the past month:

	Start	End			%	%	%
Poll	date	date	Size	MOE	D	R	Diff
Rasmussen	14-Sep	14-Sep	750	4.0	51	46	D+5.0
CNN Time OR	10-Sep	14-Sep	906	3.0	53	44	D+9.0
Elway	09-Sep	12-Sep	500	4.5	50	41	D+9.0
Rasmussen	31-Aug	31-Aug	750	4.0	46	48	R+2.0
DSCC	28-Aug	31-Aug	968	—	50	45	D+5.0
SurveyUSA	18-Aug	19-Aug	618	4.0	45	52	R+7.0
Rasmussen	18-Aug	18-Aug	750	4.0	48	44	D+4.0

In what follows, I’ll ignore the DSCC poll. Not that I have any reason to doubt the poll. Rather, the poll was specifically released because the results favored Murray, thus clearly violating a statistical assumption used for the analysis.

Murray leads in four of the remaining six polls. As usual, I’ll begin with a Monte Carlo simulation analysis of the most recent poll (FAQ). Taking just the new Rasmussen polls there were 728 respondents who went for Murray or Rossi. Following a million simulated elections, Murray tallies 835,577 wins to Rossi’s 158,253 wins.

The evidence offered by this most recent poll suggests that Murray would have an 84.1% chance of beating Rossi if an election had occurred two days ago. Here is the distribution of outcomes from the simulated elections:

With three polls released over three days, we might as well combine all of ’em. Of the total of 2,156 individuals sampled, 2,061 go for Rossi or Murray. Murray gets 51.6% and Rossi gets 44.0% of the “votes.” The simulation analysis gives Murray 994,327 wins to Rossi’s 5,404 wins.

Thus, these three polls offer evidence that Murray would have a 99.5% chance of beating Rossi in an election held over that past week.

Rossi does a little better if we combine the last month of polls (all but the DSCC poll in the table). Now we end up with a sample of 4,274 respondents, of which 4056 are for Murray or Rossi. The raw percentages are 49.0% Murray and 45.9% Rossi. The Monte Carlo analysis gives Murray 933,103 wins to Rossi’s 65,250 wins.

If the past month of polling is representative of Washington state voters, the evidence suggests that Murray would win an election held now with a 93.5% probability.

Going back a month or two things did not look nearly so rosy for Murray. This is clear from a graph of the polling in this race:

See that dip that occurs over the summer? When the early September Rasmussen poll came out showing Rossi leading Murray 48% to 46%, I offered a theory:

There is another reason I am not (yet) too concerned. August 31 is still in the “dog days of summer” around here. In my many years of following polling in Washington state, I’ve learned that Washingtonians become very negative in the summer, only to perk right back up in the fall. I can’t really explain it…I’ve just observed it in approval numbers. Murray probably gets the worst of if from the summer malaise. That is, Murray doesn’t really have to worry about close results like these for another month….

I’m such a pessimist…it only took a couple of weeks.

(Cross posted at Hominid Views.)

Three days and three new polls in the race between Sen. Patty Murray (D) and Dino Rossi (R). Today’s poll is by Rasmussen and shows Murray leading Rossi 51% to 46%.

These new results are completely consistent with polls released over the past two days. Two days ago, an Elway poll showed Murray leading Rossi 50% to 41%. And yesterday we saw the release of a CNN, Time, and Opinion Research poll that had Murray leading Rossi by a remarkable 53% to 44%.

I’ll post more analysis of this new poll and some joint poll analyses later today.

Another day another poll in the race between incumbent Senator Patty Murray (D) and real estate speculator and perennial candidate Dino Rossi (R). Just yesterday, an Elway poll showed Murray leading Rossi 50% to 41%. I understand some folks are skeptical about the veracity of Elway’s polls, so this new poll will be interesting….

Today’s poll, by CNN, Time, and Opinion Research, queried 906 likely voters in Washington state. In the poll, Murray leads Rossi by a stunning 53% to 44%. (Among registered voters, rather than likely voters, Murray leads Rossi by 50% to 44%). That’s even more favorable for Murray than the Elway poll!

As usual, I’ll do a Monte Carlo analysis to get a better feel for the odds of each candidate winning as suggested by the new poll results. After a million simulated elections using the likely voter numbers and percentages, Murray won 973,114 times, and Rossi, 25,471 times.

In other words, if the election was held right now, the evidence from this poll suggests Murray would have a 97.4% probability of beating Rossi. Because the winning percentage is over 95%, statisticians would deem this “statistically significant.” That is, Murray’s lead isn’t very likely to be an artifact of a small sample. Here is the distribution of outcomes from the simulation:

That’s a lot of blue there….

Since yesterday’s Elway poll was taken just a few days earlier, we can reasonably combine the evidence from these two polls. There were a combined total of 1,406 “votes” of which 1,334 went to either Murray or Rossi. Murray took 51.9% of the “votes” to Rossi’s 43.0%. A series of simulated elections from the joint polls gives Murray 992,496 wins to Rossi’s 7,124 wins. In other words, these two polls suggest that Murray would have a 99.3% chance of beating Rossi if the election had been held now. Here’s the distribution:

That’s even more blue!

Clearly…the one thing Rossi is badly in need of in this race is more SurveyUSA polling!

Update: Here is what the polling looks like this year for the race….

Clearly, the summer slump has ended.

It’s primary night tonight…well, it is in DE, MA, MD, NH, NY, RI & WI (oh yeah…in DC, too). So please join us tonight for an evening of electoral politics under the influence at the Seattle chapter of Drinking Liberally. We meet at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Stop by even earlier and enjoy some dinner.

Not in Seattle? There is a good chance you live near one of the 246 other chapters of Drinking Liberally.

(And there are links to 40 more media clips from the past week in politics at Hominid Views.)

Please join us tonight for an evening of Bible burning politics under the influence at the Seattle chapter of Drinking Liberally. We meet at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Stop by even earlier and enjoy some dinner.

Not in Seattle? There is a good chance you live near one of the 245 other chapters of Drinking Liberally.

Mission Accomplished!

So stuff some socks down your flight suit and join us on the deck of the U.S.S. Drinking Liberally for an evening of political machismo under the influence. We’ll “bring it on” at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Some of us will be there even earlier for dinner.

Not in Seattle? There is a good chance you live near one of the 242 other chapters of Drinking Liberally.

(And there are over fifty more links to media from the past week in politics posted at Hominid Views.)

It is a primary election night in five states (Alaska, Arizona, Florida, Oklahoma and Vermont), so come and cheer for your favorite teabagger and spend an evening of electoral politics under the influence at the Seattle chapter of Drinking Liberally. We meet at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Some folks will be there early for dinner.

Not in Seattle? There is a good chance you live near one of the 272 other chapters of Drinking Liberally.

The winners of Tuesday’s top-two primary for the Washington state Senate race were Sen. Patty Murray (D) and real estate speculator (and perennial candidate) Dino Rossi (R). Little surprise there. Late last week, Washingtonians got a double dose of post-primary polls matching up Murry and Rossi.

Rasmussen released this poll on Thursday showing Murray leading Rossi 48% to 44% in a poll taken the day before (18 Aug). The sample of 750 is large for Rasmussen—their samples are typically 500 likely voters.

On Friday, Survey USA released a poll taken on the 18th and 19th of August, on a sample of 618 likely voters. The results? A stunning 52% to 45% lead for Rossi!

What is going on? First let me wander off-topic for a minute to point out that in my analyses of past elections, I have found both Rasmussen and Survey USA to be pretty good polling firms for head-to-head general elections. Rasmussen has a bad reputation among liberals, but that is mostly based on their presidential approval tracking poll that IS biased slightly in favor of Bush and against Obama (relative to comparable polls) for the seven years that I have been following it. But approval tracking polls are not the same type of poll as a head-to-head election poll, and Rasmussen does just fine with the latter. Survey USA is sometimes dissed as a liberal polling firm by conservatives. Whatever…their track record is pretty good. Going on just the numbers from state polls during to 2008 presidential, senatorial, and gubernatorial elections, I can’t really tell Survey USA and Rasmussen apart.

During the 2010 election season, some big differences I see is that Rasmussen has greatly increased the number of statewide polls they do; Survey USA has decreased the number of statewide races polled. I have no idea what to make of it. Anyway, onto the race.

Since these two polls were in the field simultaneously, I’ll simply combine them and do my usual Monte Carlo analysis to determine the relative probabilities of each candidate winning based on these polls. Of the combined 1,368 “votes”, Murray and Rossi got 1,289 of them; 46.6% went to Murray and 47.6% went to Rossi. When we normalize these so that they sum to 100%, Murray gets 49.5% and Rossi gets 50.5%. Even with this relatively large sample size, this is clearly a statistical tie.

After simulating a million elections using the observed frequencies and sample sizes, Murray wins 392,801 simulated elections and Rossi wins 599,396 simulated elections. In other words the two polls suggest Murray has a 39.6% probability of beating Rossi. Here is the distribution of wins:

Objectively, those are the results. But, as a Murray supporter, I am not overly daunted. This graph of the polling in this race shows why:

Notice anything odd?

Both of the Survey USA polls conducted for this race favor Rossi uncharacteristically strongly. Most other polls either tend to favor Murray, or show a very slight advantage to Rossi. That’s odd. In fact, when the first Survey USA poll came out, neither camp believed it. I wonder if the Rossi camp believes it now?

Personally, I’m skeptical about the poll. It seems like something is going wrong for Survey USA. And looking at the cross tabs doesn’t help. As N in Seattle points out in the Horses Ass comment threads:

If you take a look at the very last column in the survey’s crosstabs, you’ll see that they show Murray and Rossi tied in “Metro Seattle”.

Really? Murray and Rossi tied in Metro Seattle? I doubt it. N in Seattle shows why:

Based on the population proportion, I assume that means King/Pierce/Snohomish Counties.

We’re now counting a rather more comprehensive “survey”, the primary election. In those three counties, Patty has 53% of the vote to Dino’s 30%. SUSA is asking us to believe that in the general election:

a) about 10% of Patty’s primary voters will switch to Rossi, and

b) every primary voter who chose someone other than Patty will vote for Dino, and

c) the voters who sat out the primary but will vote in the general election (about 1/4 of the electorate, and more strongly Democratic than primary voters) will follow the same pattern as in a) and b)

All of the above would have to happen in “Metro Seattle” for Dino to tie Patty here. It ain’t gonna happen. In fact, it ain’t even gonna happen in the rest of Democratic western Washington either.

I suspect even Dino Rossi would agree with N’s analysis.

Notice that there are two other fairly recent polls on the graph. The earliest is another Rasmussen poll of 750 likely voters taken on 28th of July, and showed Murray up 49% to 47%. That is pretty close to tied. The second (in blue) is from Public Policy Polling (PPP) taken on 27th of July to the 1st of August on 1,204 registered voters. This poll showed Murray leading Rossi, 49% to 46%.

The PPP poll surveyed both the primary election and the general election, which gives us the chance to do a little accuracy-checking. For the primary, PPP found that Teabagger Clint Didier would get about 10% of the vote, Murray would get 47% and Rossi would get 33%. As of Sunday evening, Diddier is at 12.6%, Murray is 46.4% and Rossi is 33.3%. Pretty much spot on, considering it was taken about 18 days earlier.

One last exercise for your consideration. If we combine all four polls taken within the last month, and do the same Monte Carlo analysis, things turn around. There is a total of 3153 votes for either Murray or Rossi, Murray gets 50.6% of them,and Rossi gets 49.4%. Now, Murray wins 682,212 simulated elections, and Rossi wins 313,150 of them. In other words, these four polls give evidence that Murray would win with a 68.5% probability. And that includes the Survey USA poll! Here is the distribution…

The take-home message is that the contest, at this point, is pretty close. But I think the more interesting question that arises from all this is…what the hell happened to Survey USA?!?

(Cross-posted at Hominid Views.)

(And there are links to some 45 other media clips from the past week in politics at Hominid Views.)

It is a primary election night in Washington State. So please drop off your ballot and then join us for an evening of electoral politics under the influence at the Seattle chapter of Drinking Liberally. We meet at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Some folks will be there early for dinner.

Not in Seattle? There is a good chance you live near one of the 276 other chapters of Drinking Liberally.

Via West Seattle Blog:

[The following] video is getting West Seattle a bit of national attention tonight in the ongoing controversy over Target’s donation to a Minnesota candidate with a history of opposing gay rights. The musical protest took place in the Westwood Village Target store on Saturday, apparently around 11 am

It is election night in Colorado, Connecticut, Minnesota and Georgia, and there’s a lot of teabaggery at stake. So please join us for an evening of electoral politics under the influence at the Seattle chapter of Drinking Liberally. We meet at the Montlake Ale House, 2307 24th Avenue E. beginning at about 8:00 pm. Some folks will be there early for dinner.

Not in Seattle? There is a good chance you live near one of the 276 other chapters of Drinking Liberally.

(And there are about 50 more links to the past week in political media at Hominid Views.)