Must Read for novice poll sniffers; Learn about The 50% Rule

[Rose Siding]

snipped from kos...

We're always talking about the 50 percent rule, but it's rarely explained. And given all the new people visiting the site, it's time for a refresher course. I'll steal Mystery Pollster's explanation.

The basic idea is that voters make their decisions differently in races involving an incumbent. When newcomers vie to fill an open office, voters tend to compare and contrast the candidates' qualifications, issues positions and personal characteristics in a relatively straightforward way. Elections featuring an incumbent, on the other hand, are as Molyneux puts it, "fundamentally a referendum on the incumbent." Voters will first grapple with the record of the incumbent. Only if they decide to "fire" the incumbent do they begin to evaluate whether the challenger is an acceptable alternative.

Voters typically know incumbents well and have strong opinions about their performance. Challengers are less familiar and invariably fall short on straightforward comparisons of experience and (in the presidential arena) command of foreign policy. Some voters find themselves conflicted -- dissatisfied with the incumbent yet also wary of the challenger -- and may carry that uncertainty through the final days of the campaign and sometimes right into the voting booth. Among the perpetually conflicted, the attitudes about the incumbent are usually more predictive of these conflicted voters' final decision than their lingering doubts about the challenger. Thus, in the campaign's last hours, we tend to see "undecided" voters "break" for the challenger.

That's the theory. Does it have any empirical support?

In 1989, Nick Panagakis, president of Market Shares Corporation (the firm that polls for the Chicago Tribune) analyzed results from 155 surveys, most from the late 1980s, all conducted during the last week before an election. In a famous article in The Polling Report, Panagakis found that in 82% of the cases, the undecideds "broke" mostly to the challenger.

His conclusion? "Incumbent races should not be characterized in terms of point spread. a poll shows one candidate leading 50% to 40%, with 10% undecided...Since most of the 10 points in the undecided category are likely to go to the challenger, polls are a lot closer than they look - 50% to 40% is likely to become 52% to 48%, on election day" (emphasis added).

Just last month, Chris Bowers of MyDD updated Panagakis' work. Though he found some signs that the incumbent rule might be weakening in state and local races, he found even stronger support for it in presidential elections. In 28 surveys involving presidential elections, 86% showed undecideds breaking mostly to the incumbentchallenger.

Going back to the polling data at 2.004K, it's also interesting to see the number of supposed safe Bush states that are hovering on or just above 50 percent.

Kerry is tantalizingly close to breaking the race wide open and getting the sort of landslide victory that would conclusively repudiate the Bush agenda.

http://www.dailykos.com/story/2004/10/20/104048/91

[TruthIsAll]

1. And that is why the Election Model has a 97% win probability for Kerry

http://www.geocities.com/electionmodel/

[Rose Siding]

2. Yes, it makes sense now

kick- It helped me.

[DinahMoeHum]

3. Basically, if an incumbent is not polling at 50% or more by this time

you can stick a fork in him - he's done.

:kick:

[kaitykaity]

4. Gee, you'd think the media whores would have

access to this same information.

:shrug:

[Zero Gravitas]

5. They do

but it is not their job to be impartial purveyors of information (although, of course, it should be). Their idea of being "balanced" is to put out eqiual amounts of good/bad news to each side, and these days most of them don't even bother with doing that, they just say whatever they think will help Bush without being too obvious about it.

[cthrumatrix]

7. IMHO they go out of their way the past 4 yrs to protect the idiot in chief

[kaitykaity]

8. May they all be flogged in the public square.

I wonder if it's possible to embarrass them into that
responsible impartial journalism thing? Somehow I doubt it.

[Eurobabe]

6. my gut says if BOOSCH ain't pullin above 50%

after being in office for 4 yrs., he stands a snowballs chance in hell of getting re-selected. Unless the fawker cheats!

[Shadow30]

9. Very interesting and helpful thanks....

...there is one thing I am wondering.In most polls I see they refer to likely voters being polled what exactly is a likely voter by there definition?I am just curious is there any kind of standard criteria for defining a so called "likely voter" in polls or does it vary?Can anyone help me with this?Thanks.

[crispini]

12. No, there is not

any one standard for evaluating who "likely voters" are ... this is why these numbers vary so widely from poll to poll.

[Nicholas_J]

10. Lets put it this way, even Carter

Had a larger lead over Reagan during the last weeks of the electiond than Bush has over Kerry. If he has a lead at all in many polls.

In a race like this in which the incumbent is running neck and neck with the opposition, it is relatively clear that the incumbent simply has little credibility among those who are holding back.

[Poiuyt]

11. Kick

Good summary

[Awsi Dooger]

13. In 28 surveys, 86% showed undecideds breaking mostly to the challenger

That does not say 86% of the undecideds break toward the challenger.

I've studied polls and results since '96. Breaking them down by different types of pre-election poll numbers -- 50/50, 5 point race, 10 point race, 15+ point race -- it's clear undecideds break least toward the challenger in a 50/50 atmosphere. I'm conservatively estimating Kerry's share at 62-63%.

[Homerr]

14. 24 of 28 polls = 86%, not 86% of undecided voters?

[Awsi Dooger]

15. That's the way I read it

I just looked at Chris Bowers' analysis of the incumbent rule on MyDD.com. Bowers is very good, but he admits he doesn't have much to work with regarding poll numbers and presidential races. He studied 450+ polls in state and local races to just 28 in presidential.

Here is an article that looks at how undecideds break in presidential races since 1936. http://www.dalythoughts.com/Update-05-26-04.htm

For some reason I was unable to copy and paste the data. The chart is down the scroll, and not the first chart. I don't understand the polls used in the chart. It lists the poll number one month out, then the "next to last poll." I have no idea why the final poll was not used, or if it changed the conclusion significantly.

Bottom line according to that chart: doesn't look like undecideds break automatically or sharply toward the challenging party in presidential elections.