Patterico's Pontifications

1/10/2010

What’s up with the Mass. Senate polls?

Filed under: General — Karl @ 10:22 am



[Posted by Karl]

The new Boston Globe poll showing Democrat Martha Coakley beating Republican Scott Brown by 15-points in the race for Ted Kennedy’s Senate seat, when contrasted with Public Policy Polling showing a dead heat, has people scratching their heads. So what’s up with that?

TPM’s Josh Marshall claims it is “all about the screen,” referring to how each poll selected likely voters. The two polls do appear to screen differently — the Globe specifically asked, while PPP selects voters in recent elections (Personally, I prefer the latter). But Marshall is almost certainly wrong that it’s all about the screen. AmSpec’s Philip Klein does a much better job of outlining differences between the two polls: (1) The Globe sample is much more Democratic; (2) PPP has Brown winning Independents by a huge margin; (3) PPP polled after the Globe. But the differences do not stop there. The Globe poll used a smaller sample, producing a larger margin of error. The Globe poll used live interviewers, while PPP uses automated calling. The sequencing of key questions also differs. For example, PPP started by asking for whom the respondent would vote, while the Globe asked about party registration and candidate favorability first. The Globe specifically included Independent candidate Joe Kennedy, while PPP did not (though one might have expected a faux Kennedy to hurt Coakley, that turned out not to be the case).

The import of the first two factors Klein identified is crystallized in his observation that the Globe only polled 83 independents, while PPP polled about 290. The Globe asked specifically in terms of registration, while PPP did not, which may account for some of the gap. Even so, there will be a much larger margin of error in a sub-sample as small as 83. These issues also filter down to the different results on candidate favorability in both polls — the Globe speaks of Coakley’s “durable statewide popularity,” which you do not see in the PPP results.

One point of agreement between the two polls is the role of relative intensity. PPP reports that “66% of GOP voters say they are ‘very excited’ about casting their votes, while only 48% of Democrats express that sentiment.” The Globe reports that “Brown matches Coakley – both were at 47 percent – among the roughly 1 in 4 respondents who said they were ‘extremely interested’’ in the race.” Some might be tempted to frame these numbers as an “enthusiasm gap,” though it is probably more accurate to note that the Right tends to vote more regularly than the Left, and that the key for Coakley will be turning out enough of the state’s much larger pool of Democrats.

Finally, I should add a note about PPP. The news accounts (and blog commenters in stories involving PPP) almost always note that the Democratic firm infamously showed Conservative Doug Hoffman leading Democrat Bill Owens by 17 points in its final poll of the NY-23 Congressional special election last November (Owens won by 4 points). There were a number of practical problems with polling that particular election, though I do not think they fully explain PPP’s call. Rather, everyone should remember that the margin of error reported by most polls assumes a 95% confidence interval. That means that given repeated samples, 19 of 20 would produce results for any given question falling within the stated margin of error. PPP’s call in NY-23 was likely that bad outlier for which the risk always exists, even with the best of pollsters. That is why it is always better to have more than one poll to examine, even if the results are maddening when we have only two to examine.

–Karl

20 Responses to “What’s up with the Mass. Senate polls?”

  1. Karl – You have at least three polls. Didn’t Rasmussen show the race with a nine point Coakley margin at the beginning of last week?

    daleyrocks (718861)

  2. Coakley has this so sewn up that there isn’t any reason to even bother to go out and vote for her. She is going to slam dunk this thing and just adding additional Coakley votes would only humiliate the other side, which is always a bad thing. It would be like a high school basketball team leading by 60 points that continues to score and score.

    Coakley supporters would be much better off if they spent their time sticking pins in a Sarah Palin doll than going out in the 4 inches of global warming that is likely to be covering the sidewalks and streets just to vote for a race that is already decided.

    Huey (b957d9)

  3. If Rasmussen shows the liberal Democrat ahead — and comfortably ahead — in Massachusetts, then that news in general is along the lines of “the sun is hot, the South Pole is cold!”

    The Kennedy family’s home state is so bogged down by limousine liberals (a characterization that applies to people’s behavior regardless of their income level) that for any common sense and logic to seep out of it is unfathomable and a phenomenon next to miraculous.

    Mark (63f90e)

  4. Rather, everyone should remember that the margin of error reported by most polls assumes a 95% confidence interval. That means that given repeated samples, 19 of 20 would produce results for any given question falling within the stated margin of error.

    Best definition of a confidence interval —evah!

    Thanks Karl!

    Pons Asinorum (68944a)

  5. Hmmm. Releasing a poll that shows a Democrat is far ahead, just at the time that Republicans think they have a shot in this election?

    Is this this same press that has developed quite the reputation for partisanship of late? Of hiding information that hurts their own candidate?

    I could be wrong. But the timing is very, very suspicious.

    But heck, we’ll know that the Right has a chance in this election when the Lamestream Media starts spitting and hissing that even if Brown wins, ObamaCare can’t be stopped.

    Wait a minute….

    Eric Blair (ddbceb)

  6. I’ve read every single online MA newspaper I can find, and consistently, Dems in droves are voting for Brown. IMO, when the Brown camp releases fundraising $$’s after tomorrow’s moneybomb, jaws will drop.

    sybilll (f744a0)

  7. Huey – Great ideas! I suggest you post your comment to the Globe website!

    daleyrocks (718861)

  8. In 1994, I remember that there was NO ONE who predicted the results of the election correctly. There were comments about the possibility of major D losses but NO ONE predicted that both houses would change. Why ?

    The conventional wisdom held that it could not happen. After all, the Democrats had ruled the House since 1950. That is what we are seeing in Massachusetts, I believe.

    I think there is also an underground that still thinks about the Amirault case and wants to see every Democrat politician who was involved in that miscarriage of justice driven from public life.

    For example. This is far beneath the radar for most non-Mass residents.

    Mike K (2cf494)

  9. daleyrocks,

    You’re right about the Rasmussen poll. However, Nate Silver reverse-engineered the Rasmussen sample, finding that it may have… wait for it… undercounted Independents. The key phrase being “may have,” as we can’t know the composition of the electorate in advance, esp. in a special election. But it does underscore that the polling in this race is being driven largely by assumptions about Indies.

    Karl (cc4af5)

  10. […] At Patterico, I was asked about the earlier Rasmussen poll that showed Coakley up by 9 points. Interestingly, […]

    The Greenroom » Forum Archive » What’s up with the Mass. Senate polls? (e2f069)

  11. Karl – Those Chowderheads can be an unpredictable lot.

    daleyrocks (718861)

  12. Given the movement from the Rasmussen poll to the PPP poll, a time interval of about a week, it’s probably fair to assume that this race is changing rapidly. Unpredictably too. PPP made the point that turnout will determine who wins and they might be right.

    MTF (a20706)

  13. The Globe conducted its poll entirely within their own office.

    the wolf (7cffb6)

  14. Nah, it wasn’t that encompassing, it was just the Editorial Board.

    AD - RtR/OS! (6a5c0d)

  15. Karls right and let me add something else

    Democrats are experiencing nation wide a small reverse in party registration numbers and those who identify themselves as democrats

    Additionally, the minority vote is huge in Mass, cannot see them turning out as unemployment, high taxes and gay marriage usually keep some of the more dependabler minority voters uninterested and less likely to stand in cold weather to vote or to vote early

    EricPWJohnson (195634)

  16. I’m just hoping that Brown wins, because I want to be the first person to say “Lame Duck Congress.”

    Kevin Murphy (3c3db0)

  17. This is only the third politician to whom I have given money:
    Sarah Palin, Joe Wilson and now Scott Brown.
    Goooooooooooo Scott!

    Krusher (fad639)

  18. Having been born and raised in Mass. and still having contact with family and friends I’d like to propose the following theory.

    Massachusetts voters are suffering from sticker shock.

    Yes they celebrated the wonderfulness of Obama’s victory, every bit as much for the “not Booosh” aspect as for the transcendent historical racial aspect. “We’ll have a smart, well spoken head of state who will erase the perception of America as jingoistic dummasses, ushering in a new era of multilateral intelligentsia.”

    What I’m hearing now is even big government liberal die hards are stunned at the shear scope and breadth of the ruinous deficit and the administration’s and Congress’ lack of interest in restraining their spending at all. What has enraged conservatives has both confused and alarmed many liberals and, most importantly, a host of independents.

    If the stars align and Brown pulls this off, the Dems have no shot whatsoever to pass this off as a “fancy” like they did with Virginia and New Jersey (leveraging NY-23 for effect.) This was the safest seat in the Senate (along with WV’s Byrd) held by a man who was an iconic figure for both The Democratic Party in general and progressives in particular. It’s defeat would (and should) shake the party to its very core. No amount of spinning would alleviate its impact.

    Cold weather and voter alarm? It could, might just happen.

    BJTexs (ccd51f)

  19. […] the polls may say (and Scott Rasmussen has more on that), the fact that the DNC is sending a senior press […]

    The Greenroom » Forum Archive » The Mass. Senate race… and beyond (e2f069)

  20. Mike, that’s a very disturbing link. I think about that case occasionally, and was sorta aware of Martha’s involvement, but I hadn’t realized that her involvement was so long after it was obvious this was a miscarriage of justice. What a pathetic and bitter person Coakley must be. Most prosecutors would take pride in fixing a mess like that.

    You’d think they could find a better liberal in all of Mass than this lady.

    They say weather will be 33 degrees on election day. That’s going to make a huge difference in an election that’s bound to be a mess. People are motivated to fight Obama. I just don’t think the left has the heart to see this one through. Even a near tie is demoralizing for team D.

    Dustin (b54cdc)


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