538 Model Debut: 64% Chance of Republican Majority; R+7 Most Likely

[SPC]

They give Republicans a 64% chance:
Illinois: 11%
New Jersey: 11%
Minnesota: 13%
New Hampshire: 19%
Michigan: 30%
Iowa: 52%
Colorado: 53%
North Carolina: 54%
Alaska: 54%
Arkansas: 66%
Georgia: 70%
Louisiana: 71%
Kentucky: 77%
Kansas: 79%
South Dakota: 87%

[dmmidmi]

About f'ing time.

[Maxwell]

I'd say Colorado is a tad generous.

[Senator Cris]

I'd say Colorado, Illinois and New Jersey are a tad generous.

[eric82oslo]

I'd say Colorado is a tad generous.

Except for Illinois, New Jersey and New Hampshire, they're all way generous.

[backtored]

I'd say Colorado is a tad generous.

I'd say not.

[Maxwell]

I'd say Colorado is a tad generous.

I'd say not.

So Udall leading in most of the polling (even if its narrow) leads to a 52% chance that Gardner would win? Come on dude.

[Amenhotep Bakari-Sellers]

We,are really where we have been since July, a holding pattern of GOP net 5 and La goes to runoff.

Absent of a GOP wave

[backtored]

I'd say Colorado is a tad generous.

I'd say not.

So Udall leading in most of the polling (even if its narrow) leads to a 52% chance that Gardner would win? Come on dude.

The polling has been basically dead even and the localized variables are pretty encouraging for Republicans.  The number is totally plausible given the optimism in this model with regards to other GOP opportunities.  I've always felt that Alaska and North Carolina are as likely to flip as Colorado, and the model gives a 53% shot at those two states flipping.  So, yeah, it seems legit.  

The Upshot gives Udall a 57% shot at winning. WaPo gives him a 63% shot at winning, which makes sense for a model that is increasingly pessimistic about GOP chances overall.  Incidentally, the WaPo model actually gives Gardner greater likelihood of winning than either Sullivan or Tillis, which vindicates my thinking about CO versus AK and NC.  

I think all of these are fair projections.  Some are more optimistic, some not so much.  We'll see what happens.  I happen to think that Gardner will actually win, but I'm okay with anything between 40 and 60 percent, because most likely the race is 50/50 at this point.  If Pryor hangs on and Hagan wins big and there is obviously no wave, then I probably will be looking for a Udall win.  But if Republicans are doing well all over the map, then I absolutely think Gardner wins. 

[backtored]

We,are really where we have been since July, a holding pattern of GOP net 5 and La goes to runoff.

Absent of a GOP wave

I think that a lot of people expected the GOP to break out over the summer in a least a few of the competitive races.  But it hasn't happened.  Part of the problem is that a lot of the polling has been sucked up by Kentucky and Georgia, even though those states probably aren't as competitive as people think.  And you can add Kansas to that list.  Colorado hasn't been polled for over a month, and I haven't seen a good Louisiana poll in a long time.  Alaska is hard to poll, but only Rasmussen and PPP have even bothered in the last month.

Nobody actually knows how those states are because we're too busy playing around with fantasy scenarios like Kansas keeping the Senate in Democratic hands. 

You're right we're in a holding pattern, but a lot of that is caused by a dearth of good polling.  The polls we do have indicate that Democrats are doing a good job hanging tough in races that they should be down in.  We'll need more polling to see if that is true.

[dmmidmi]

I'd say Colorado is a tad generous.

I'd say not.

So Udall leading in most of the polling (even if its narrow) leads to a 52% chance that Gardner would win? Come on dude.

The polling has been basically dead even

This is bullsh!t.

http://en.wikipedia.org/wiki/United_States_Senate_election_in_Colorado,_2014

Since April, Udall has led in 17 polls. Gardner has claimed a lead in four. Just because polling has been close, it doesn't mean you can ignore that Udall has been leading in nearly every single poll this year.

[Never]

I can't say I believe Republicans have a 54% chance of winning the Senate race in Alaska. It seems risky to try and adjust polling to fit a model as 538 did in a state like that.

Still, Nate Silver did note that most Senate prediction models will probably have a notable number of faulty calls this year:

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[Lief 🗽]

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But but but... Nate Silver doesn't make calls! He makes "probabilities" (and thus can never be wrong)!

[Brittain33]

Alaska could very easily slip through the same small-state hole in Silver's model that Montana and North Dakota fell through last time.

[7,052,770]

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But but but... Nate Silver doesn't make calls! He makes "probabilities" (and thus can never be wrong)!

That is correct.  Why does this bother you so much? He can't ever be "right" either, and never claims to be.

[dmmidmi]

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But but but... Nate Silver doesn't make calls! He makes "probabilities" (and thus can never be wrong)!

The beauty of hedging your bets.

[free my dawg]

Meh. Wang is better anyway.

[backtored]

I'd say Colorado is a tad generous.

I'd say not.

So Udall leading in most of the polling (even if its narrow) leads to a 52% chance that Gardner would win? Come on dude.

The polling has been basically dead even

This is bullsh!t.

http://en.wikipedia.org/wiki/United_States_Senate_election_in_Colorado,_2014

Since April, Udall has led in 17 polls. Gardner has claimed a lead in four. Just because polling has been close, it doesn't mean you can ignore that Udall has been leading in nearly every single poll this year.

And since June there have been seven polls, and Udall has led in four, including the dubious YouGov.  Two of those leads were of only one point. Gardner has led in three.

Four versus three and you're honestly arguing that Udall has a clear lead?

It doesn't make sense go all the way back to April and cite leads for Udall of four points in a PPP poll when PPP now shows Udall only up one.  I don't care about April's PPP poll. I care about the August PPP poll, which is obviously a more accurate depiction of where the race is today, and not four months ago. 

If your point is that Udall led in April, well, okay.  If anything, that only proves my point because while Udall led in April, polling shows a dead-even race today, which means that Gardner is actually gaining.

[muon2]

One of the differences about Silver's model is that it generates both a most likely result and a 90% confidence spread. Both of those are important to the overall simulation, and to the individual race chances.

For example, for SD he shows a central value of R+12 and for IL the central value is D+9. Naively one might expect the Pub in IL to have a significantly better chance than the Dem in SD. However, the 90% confidence limits in SD are plus or minus 16, while in Il they spread is plus or minus 13. The result is that there is about the same spread that crosses the center line, so the probability of an upset is comparable, 13% in SD and 11% in IL. The difference between those requires knowledge of the values to at least one decimal place which isn't given on the graphic.

Speaking of difference in upset chances, I would note that there is little statistical difference between 11% and 13% given the size of the 90% confidence spreads in their model. Similarly there is little difference in 52% or 54%, or even if they were flipped the other way. Based on the spreads, I would round off the chances to the nearest 10%. However, small changes in polling could cause apparently large jumps, such as a shift from 52% to 56% would be magnified to a shift from 50% to 60%. Given the wide and generally less sophisticated readership on matters of statistics, I would expect that a 10% jump would get far more attention than it would deserve. That might be part of the reason that they are reporting the accuracy of the chances in each race to such a degree - it diminishes the reactions to normal statistical shifts in the data.

[Fuzzybigfoot]

Weiland has a 13% chance of winning?  Double digits?  Rock on. 

[Torie]

One of the differences about Silver's model is that it generates both a most likely result and a 90% confidence spread. Both of those are important to the overall simulation, and to the individual race chances.

For example, for SD he shows a central value of R+12 and for IL the central value is D+9. Naively one might expect the Pub in IL to have a significantly better chance than the Dem in SD. However, the 90% confidence limits in SD are plus or minus 16, while in Il they spread is plus or minus 13. The result is that there is about the same spread that crosses the center line, so the probability of an upset is comparable, 13% in SD and 11% in IL. The difference between those requires knowledge of the values to at least one decimal place which is given on the graphic.

Speaking of difference in upset chances, I would note that there is little statistical difference between 11% and 13% given the size of the 90% confidence spreads in their model. Similarly there is little difference in 52% or 54%, or even if they were flipped the other way. Based on the spreads, I would round off the chances to the nearest 10%. However, small changes in polling could cause apparently large jumps, such as a shift from 52% to 56% would be magnified to a shift from 50% to 60%. Given the wide and generally less sophisticated readership on matters of statistics, I would expect that a 10% jump would get far more attention than it would deserve. That might be part of the reason that they are reporting the accuracy of the chances in each race to such a degree - it diminishes the reactions to normal statistical shifts in the data.

The irony being of course, that in reality, it is these single digits as to where the swing voters really are (fewer and fewer of them being around), so if the polls were precisely accurate (ludicrous of course), a movement of 4 points or whatever would be almost a plate tectonic shift politically.

[JRP1994]

Guys, if you add up the individual probabilities, the model is projecting R+9.

[GaussLaw]

Guys, if you add up the individual probabilities, the model is projecting R+9.

'
But events aren't independent here.  The races tend to go together.......

Thus, you can't just add up expected values like that.

[○∙◄☻¥tπ[╪AV┼cVê└]

IL, NJ, and SD seem a little less competitive than that.

[○∙◄☻¥tπ[╪AV┼cVê└]

Guys, if you add up the individual probabilities, the model is projecting R+9.

I think you missed the fact that GA, KY, and KS are currently Republican held seats.