So what the hell is going on in Colorado?

[Maxwell]

That's why RCP averaging isn't exactly the best method to use. Individual polls are closer. Though, to be fair, I think a lot of polls under-estimated that dead in the water Republican candidate's performance in 2010.

[SPC]

Where does this whole "Democrats close well" thing come from? Buck? He was just as much of a loon as Angle, and you didn't see Heller or Sandoval suddenly lose out of nowhere, nor does that stigma exist AT ALL in Nevada. It is about the candidate, and Gardner is a fantastic candidate. Is he up 6? No. Is it conceivable that he is up about 2? Sure.

While Heller didn't lose, he did come a lot closer to losing than the polls said he would. As for Buck, while he is the most notable case of Colorado Democrats overperforming the polls (because it actually changed the eventual victor), it's a notable trend regardless. Here's the data:

2004 RCP: Bush +5.2
2004 final margin: Bush +4.7
Bias: R+0.5

2004 RCP: Salazar +4.5
2004 final margin: Salazar +3.9
Bias: D+0.6

2006 RCP: Ritter +18.7
Final margin: Ritter +16.8
Bias: D+1.9

So far, these seem like fairly typical variations.

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These at first glance seem to be fairly evenly distributed once more. However, try omitting notoriously bad pollsters (Rasmussen, ARG) from the RCP Average and adding in credible ones (PPP), which gives a final average of Obama +7.3 (R+1.7) and Udall +13 (D+2.7).

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Again applying the above methodology, the Rassy-free averages are Buck +1.5 (R+2.4) and Hickenlooper +8.3 (R+6.3). Buck's loss does not seem as extraordinary in this light, and Hickenlooper's larger than expected margin can be explained by many Tancredo voters voting for the Republican Maes in order to ensure Republican Party ballot status, rather than backing Tancredo's futile bid.

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Again, omitting Rassy, ARG, and WAA gives Obama +3.3 (R+2.1)

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After corrections: R+1.0
Excluding the 2010 gubernatorial election (for the above described reasons): R+0.2

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Based on my analysis, the alleged Republican bias in Colorado polling appears to be indistinguishable from a phenomenon resulting from disproportionate polling of the state by Rasmussen and other firms with known GOP house effect. Unless Gardner is leading by a percentage point or less in a Rassy-free polling average (he's currently at +0.2 if you trade Rassy for PPP and add the Marist poll in), I see little reason to believe that some polling theory of dubious validity will push Udall (or Hickenlooper, for that matter) over the top.

[SPC]

And here's Nevada, since you mentioned that:

2004 RCP: Bush +6.3
Final margin: Bush +2.6
Bias: R+3.7

2006 RCP: Gibbons +4.0
Final margin:Gibbons +4.0
Bias: None

R2K (which is now known to be a complete fraud) was 1/3 of the average in 2006. I'll let the Rasmussen inclusion slide since their House effect did not seem to become particularly prominent until 2008. This leaves an average of Gibbons +3.0 (D+1.0)

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Exchanging Rasmussen for PPP here did not significantly affect the average. I will give you this one.

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Rasmussen did not have a big affect here either. Another peculiarity.

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Here, however, excluding Rasmussen from the average reduces Sandoval's lead to 13.5 (R+3.2)

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Eliminating Rasmussen and Gravis make this Obama +3.7 (R+3.0)

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Rassy did not play a big role here either.

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Unlike Colorado, the polling does seem to support the idea that Democrats outperform the polls by ~4% in Nevada. However, given that this phenomenon seems to be unique to Nevada (the Colorado hypothesis seems dubious upon further inspection and I do not see similar analyses for California, Arizona, or Texas), I think that it is a reach to consider this a virtue of Nevada's Hispanic population, rather than some other factor not yet proposed.

I am not sure that this stands up to any greater scrutiny than the Hispanic theory, but could Nevada's "None of These Candidates" option by playing a role here? It is possible that disgruntled conservative voters may ultimately choose the NOTC at the last minute while having previously pledged to hold their nose for the often-flawed Republican candidate.

[Miles]

I am not sure that this stands up to any greater scrutiny than the Hispanic theory, but could Nevada's "None of These Candidates" option by playing a role here? It is possible that disgruntled conservative voters may ultimately choose the NOTC at the last minute while having previously pledged to hold their nose for the often-flawed Republican candidate.

Seems like Democrats were more likely to vote NOTC. Heller and Romeny each got about 46%. PPP's final poll had Berkley's favorables down to 39/55 while Heller's approval was +5. 20% of Democrats had an unfavorable view of Berkley, and would have been likely NOTC voters.

[IceSpear]

You make some good points regarding Colorado, but even if the polling theory doesn't hold up when you exclude certain firms, the fact remains that even trustworthy and reliable firms have had a slight Republican skew in Colorado in the past two elections. Additionally, there's the vote by mail factor. I already did an analysis of this in another thread, but in the other two states with vote by mail, one had little to no effect on the polling averages (Oregon) while the other consistently underestimated Democrats (Washington). This inserts even more uncertainty into the equation, especially since this is Colorado's first vote by mail election. The "catch" is that both of these uncertain factors are in the Democrats' favor. Either the polling is going to not have a Republican skew or it will, meaning the effect will be either neutral or favoring Democrats. Same for vote by mail, there's really no scenario in which one could imagine this benefitting Republicans, meaning the only possibilities are that it will be a neutral factor or will favor Democrats. There's the possibility that the polling average could favor Democrats, but it seems very slim considering the history of the state.

As for Nevada, Miles beat me to it. I'm not sure about the other races, but the only reason Shelley Berkley isn't a senator right now is because a bunch of Obama voters couldn't stomach her and voted for NOTA or a fringe independent candidate.

[backtored]

The irony is that Udall has been one of the few Democrats in Colorado to actually underperform.  And, yet, because Michael Bennet beat expectations four years ago suddenly that makes Udall’s deficit in the polls a good thing?  Perhaps the argument should be that Udall is actually poised to do worse than what the polls now show because of Colorado’s electoral history. 

[Person Man]

I have a lot of trouble seeing Bennett as being a better pol than Udall.

[SPC]

You make some good points regarding Colorado, but even if the polling theory doesn't hold up when you exclude certain firms, the fact remains that even trustworthy and reliable firms have had a slight Republican skew in Colorado in the past two elections.

Two elections out of the last eight does not seem like particularly strong evidence for polling bias, especially when such a bias was only ~2% for the Republican candidate once the quality of the firms was controlled for. Seems almost like an invocation of the Texas sharpshooter fallacy, IMHO.

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The fact that Oregon did not have a bias while Washington did would seem to suggest that vote-by-mail is not a definitive factor suggesting Democratic overperformance. Did Washington's polling bias become worse with time, as vote-by-mail became more prevalent and eventually universal?

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Pascal's Wager is not a very convincing argument.

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Recent history seems to indicate that anything from a ~3% overestimation of the Democrat (e.g. 2008 Senate) to a ~2% overestimation of the Republican (e.g. 2010 Senate) is within the realm of possibility. Thus, I see little reason for Democrats to think of consistent but small deficits in recent polling as anything but a cause for alarm.

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Yes, looking at the exit polls, it does appear that NOTC voters were disproportionately Democrats. Mea culpa.

[SPC]

The effect that vote-by-mail has had on Washington polls:

2012 President:
Average: Obama +14.0
Actual: Obama +14.9
Error: R+0.9

2012 Senate:
Average: Cantwell +23.0
Actual: Cantwell +20.9
Error: D+2.1

2012 Gubernatorial:
Average: Inslee +1.0
Actual: Inslee +3.0
Error: R+2.0

2010 Senate:
Average: Murray +1.3
Actual: Murray +3.8
Error: R+2.5

2008 President:
Average: Obama +15.7
Actual: Obama +17.2
Error: R+1.5

2008 Governor:
Average: Gregoire +6.7
Actual: Gregoire +6.4
Error: D+0.3

Average Error: R+0.8

If Colorado's switch to vote-by-mail is supposed to save Udall, he better hope that his average polling deficit is still within a percentage point on Election Day.

[IceSpear]

These were the numbers I got.

It seems the polling in Washington is pretty consistently more Republican leaning than the final results.

2004 RCP: Kerry +4.5
Final margin: Kerry +7.2
Bias: R+2.7

2006 RCP: Cantwell +13.3
Final margin: Cantwell +17.0
Bias: R+3.7

2008 RCP: Obama +13.0
Final margin: Obama +17.2
Bias: R+4.2

2008 RCP: Gregoire +3.4
Final margin: Gregoire +6.4
Bias: R+3.0

2010 RCP: Murray +0.3
Final margin: Murray +3.8
Bias: R+3.5

2012 RCP: Obama +10.5
Final margin: Obama +14.9
Bias: R+4.4

2012 RCP: Cantwell +20.4
Final margin: Cantwell +20.9
Bias: R+0.5

2012 RCP: Inslee +1.0
Final margin: Inslee +3.0
Bias: R+2.0

Average Republican bias: 3 points

[KCDem]

No point arguing, folks. Udall will win easily.

[Antonio the Sixth]

So what the hell is going on in Iowa now? How in the world is this actually happening?

[SPC]

These were the numbers I got.

It seems the polling in Washington is pretty consistently more Republican leaning than the final results.

2004 RCP: Kerry +4.5
Final margin: Kerry +7.2
Bias: R+2.7

2006 RCP: Cantwell +13.3
Final margin: Cantwell +17.0
Bias: R+3.7

2008 RCP: Obama +13.0
Final margin: Obama +17.2
Bias: R+4.2

2008 RCP: Gregoire +3.4
Final margin: Gregoire +6.4
Bias: R+3.0

2010 RCP: Murray +0.3
Final margin: Murray +3.8
Bias: R+3.5

2012 RCP: Obama +10.5
Final margin: Obama +14.9
Bias: R+4.4

2012 RCP: Cantwell +20.4
Final margin: Cantwell +20.9
Bias: R+0.5

2012 RCP: Inslee +1.0
Final margin: Inslee +3.0
Bias: R+2.0

Average Republican bias: 3 points

Again, 2008-2012 is a consequence of keeping Rasmussen and sometimes Strategic Vision in the average while sometimes excluding the Washington Poll. True, the elections from 2004 and 2006 (excluding the gubernatorial race, which you excluded for some reason) seem to have shown a polling bias in favor of Republicans, but it would seem to undermine the argument that this is attributable to vote-by-mail if these bias has diminished in recent years.

[5280]

No point arguing, folks. Udall COULD win.

Fixed

[IceSpear]

These were the numbers I got.

It seems the polling in Washington is pretty consistently more Republican leaning than the final results.

2004 RCP: Kerry +4.5
Final margin: Kerry +7.2
Bias: R+2.7

2006 RCP: Cantwell +13.3
Final margin: Cantwell +17.0
Bias: R+3.7

2008 RCP: Obama +13.0
Final margin: Obama +17.2
Bias: R+4.2

2008 RCP: Gregoire +3.4
Final margin: Gregoire +6.4
Bias: R+3.0

2010 RCP: Murray +0.3
Final margin: Murray +3.8
Bias: R+3.5

2012 RCP: Obama +10.5
Final margin: Obama +14.9
Bias: R+4.4

2012 RCP: Cantwell +20.4
Final margin: Cantwell +20.9
Bias: R+0.5

2012 RCP: Inslee +1.0
Final margin: Inslee +3.0
Bias: R+2.0

Average Republican bias: 3 points

Again, 2008-2012 is a consequence of keeping Rasmussen and sometimes Strategic Vision in the average while sometimes excluding the Washington Poll. True, the elections from 2004 and 2006 (excluding the gubernatorial race, which you excluded for some reason) seem to have shown a polling bias in favor of Republicans, but it would seem to undermine the argument that this is attributable to vote-by-mail if these bias has diminished in recent years.

There was no gubernatorial race in Washington in 2006. If you're referring to the one in 2004, I didn't include it because RCP didn't have an average for it. Same for the Senate race in 2004. Doing my own makeshift average, the gubernatorial race would've had a 1.8 point Dem bias and the Senate race would've had a 3.7 point Republican bias, so little impact on the overall margin anyway. You can exclude certain polls from the averages to reduce the bias as you have, but all of the aggregation and projection sites will not be doing so. True, some like Silver will attempt to correct for this house effect, but most people will be taking them at face value.

[SPC]

These were the numbers I got.

It seems the polling in Washington is pretty consistently more Republican leaning than the final results.

2004 RCP: Kerry +4.5
Final margin: Kerry +7.2
Bias: R+2.7

2006 RCP: Cantwell +13.3
Final margin: Cantwell +17.0
Bias: R+3.7

2008 RCP: Obama +13.0
Final margin: Obama +17.2
Bias: R+4.2

2008 RCP: Gregoire +3.4
Final margin: Gregoire +6.4
Bias: R+3.0

2010 RCP: Murray +0.3
Final margin: Murray +3.8
Bias: R+3.5

2012 RCP: Obama +10.5
Final margin: Obama +14.9
Bias: R+4.4

2012 RCP: Cantwell +20.4
Final margin: Cantwell +20.9
Bias: R+0.5

2012 RCP: Inslee +1.0
Final margin: Inslee +3.0
Bias: R+2.0

Average Republican bias: 3 points

Again, 2008-2012 is a consequence of keeping Rasmussen and sometimes Strategic Vision in the average while sometimes excluding the Washington Poll. True, the elections from 2004 and 2006 (excluding the gubernatorial race, which you excluded for some reason) seem to have shown a polling bias in favor of Republicans, but it would seem to undermine the argument that this is attributable to vote-by-mail if these bias has diminished in recent years.

There was no gubernatorial race in Washington in 2006. If you're referring to the one in 2004, I didn't include it because RCP didn't have an average for it. Same for the Senate race in 2004. Doing my own makeshift average, the gubernatorial race would've had a 1.8 point Dem bias and the Senate race would've had a 3.7 point Republican bias, so little impact on the overall margin anyway. You can exclude certain polls from the averages to reduce the bias as you have, but all of the aggregation and projection sites will not be doing so. True, some like Silver will attempt to correct for this house effect, but most people will be taking them at face value.

Hence why I advocate simply taking a Rasmussen-free arithmetic average of recent polls to obtain a forecast, rather than relying on Dean Chambers-esque methods to concoct a rosy picture.