FiveThirtyEight Update: GOP still slight favorite to win Senate

[IceSpear]

Here's my question: Have Senate projections ever overestimated DEMOCRATS? Because I vaguely remember the Republicans being slight favorites to hold the Senate in 2006 (they lost it), Republicans were supposed to hold MN in 2008 (lost), win NV/CO in 2010 (lost), and win ND/MT in 2012 (lost). I can't think of an instance when it was widely projected/opined by the pundits that a Democrat would win, then they didn't.

Of course, there's no guarantee this will continue to hold in 2014 if it is true. Just something to consider.

[IceSpear]

You guys are the definition of hacks sometimes.

http://www.realclearpolitics.com/epolls/2012/senate/nd/north_dakota_senate_berg_vs_heitkamp-3212.html
http://www.realclearpolitics.com/epolls/2012/senate/mt/montana_senate_rehberg_vs_tester-1826.html
Berg was up 5.7 points in the final RCP average.  He was consistently leading in the final string of polls.  ND was a Heitkamp miracle and it would've been impossible to call her the favorite heading up to the election. 

In Montana, Rehberg was slightly leading in the final RCP average.  That, combined with the R nature of Montana, would've made Rehberg slightly favored, as Silver projected.

Surprises happen in elections.  It is true that in 2010 and 2012 the Republicans under-performed on election day in Senate races.  This is no guarantee that such will happen in 2014. 

I definitely concur with Del Tachi's post also.

In that case, wouldn't the problem be the polls consistently underestimating the Democrats as opposed to pundits and prognosticators then? The problem is that these surprises always tend to be concentrated in the same direction (except, apparently, since 2002, quite a while ago). Since it does seem hackish at first glance, I'll do an effortpost to prove my point. Let's consider the last 3 elections.

2012 President, Popular Vote: RCP has Obama +0.7. Final margin: Obama +3.9. A pretty substantial 3.2 Republican bias among the pollsters.

2012 President, Electoral College: RCP has Romney carrying Florida, when Obama carried it. A Republican bias of 1 state.

2012 Senate: RCP has Republicans carrying MT/ND. A Republican bias of 2 seats.

2012 Generic Congressional Ballot: RCP has Republicans +0.2. Final margin: Democrats +1.2. A 1.4 point Republican bias.

2012 Gubernatorial: RCP has Republicans carrying MT. A Republican bias of 1 seat.

2010 Senate: RCP has Republicans winning CO/NV. A Republican bias of 2 seats.

2010 Generic Congressional Ballot: RCP has Republicans + 9.4. Final margin: Republicans +6.8. A 2.6 point Republican bias

2010 Gubernatorial: RCP had Republicans winning CT/IL. A Republican bias of 2 seats.

2008 President, Popular Vote: RCP has Obama +7.6. Final margin: Obama +7.3. An extremely small Democratic bias of 0.3 points.

2008 President, Electoral College: RCP has McCain carrying Indiana and North Carolina when Obama carried them. A Republican bias of 2 states.

2008 Senate: RCP has Republicans carrying MN. A Republican bias of 1 seat.

2008 Generic Congressional Ballot: RCP has Democrats +9.0. Final margin: Democrats +10.7. A Republican bias of 1.7 points.

2008 Gubernatorial: No bias

Assuming random chance, these surprises and misses should be even or very close to even between the parties. In only one of these instances was there a Democratic bias, and it ended up being the smallest of them all. If you don't see a trend here, you're either blind or a hack. Again, I'm not saying this is definitive proof of anything, but it's certainly worth considering, especially when a miss in only one or two seats could determine who ends up controlling the Senate.

We'll see soon enough whether this is just a coincidence or a trend. If this trend does continue to hold in 2014, I would hope people begin to take notice and adjust to it in their models.

[IceSpear]

I love how when Nate Silver predicts every state right in the 2012 election and forecasts an almost inevitable Democratic majority for decades to come he's an Atlas folk hero, but now that he's using the same methodologies to arrive at the conclusion of a GOP Senate come 2015 he's now unreliable or along the lines of any other Sabato or Rothenburg type.

Nice move, Atlas.  Nice move.

And I can't wait to see the waterworks here when the GOP gets to 51 on election night.

This place is flooded with Dem hacks? NO!

Literally nothing could be more hackish than predicting Rick Santorum would win in 2006, except possibly if there were Democrats predicting Blanche Lincoln would win in 2010. Are you really in a position to throw stones here?

Anyway, I was never a Nate Silver cultist. He's good at what he does and I respect his work, but he's not infallible.

[IceSpear]

Anyway, I was never a Nate Silver cultist. He's good at what he does and I respect his work, but he's not infallible.

Who's claiming that he is?

All the Silver fanboys ever claim is that when he says something has an X% chance, it usually happens around X% of the time. All this talk about being "right" and "wrong" comes from people who don't have a good understanding of probabilities.

The problem with that logic is it removes all accountability from his results. Say whichever some dude in Oklahoma manages to defeat Inhofe, it would make Silver (and everyone else, obviously) look ridiculous. But then you could simply counter with: "But Silver said there was a 1% chance that would happen, and you'd expect things with a 1% probability to occur sometimes, so Silver was still right!"

There's no way to verify his probabilities since we can't run the same elections over and over in simulations. That's why people only care about his calls, not his probabilities. And he seemed to have no problem accepting the "called all 50 states!" accolades which gave him prominence even though he was "just giving odds".

[IceSpear]

But if 1% probability events don't happen around 1% of the time, then Silver's odds aren't good. Such upsets need to happen 1% of the time. Of course it may be decades before he has enough 99%-1% calls in order to analyze how good his model is at that point (and I'm sure he'll be tweaking the model in the meantime), but so far his Senate probabilities have aligned pretty closely to real life.

He gave Heitkamp an 8% chance of victory, but that's the only winner with an ~8% chance to win, so that all looks about right. Reid and Tester were underdogs in his model too, and there have probably actually been too few upsets by his odds.

As the years go on and we get a larger sample to analyze, it may turn out that his probabilities are actually great, horrible, just OK, or anywhere in between. But right now, all we can say is that his Senate probabilities look at least decent at this point.

And he seemed to have no problem accepting the "called all 50 states!" accolades which gave him prominence even though he was "just giving odds".

Yeah, I was annoyed he didn't correct Jon Stewart when he called him "the guy who correctly called all 50 states" in the Daily Show interview, but it's not like Silver promotes himself like that. I guess Silver just isn't the statistical purist that I am since the misperceived "clean sweep" probably made him hundreds of thousands of dollars.

Yeah, there's nothing overtly staggering about his percentages (although he seems to give out 1% too liberally, for example D in OK/R in RI is definitely closer to 0% than 1%, and as you say upsets seem more uncommon than they should be). The troubling thing is that every miss he had was always being too bullish for the Republicans, same as RCP which I documented in my earlier post. This is probably more of a function of the polls themselves though, with turd pollsters like Gravis flooding the zone and cranking out pro-GOP outliers. The aggregators and forecasters are merely victims of these firms, which should be ignored.

[IceSpear]

I love how when Nate Silver predicts every state right in the 2012 election and forecasts an almost inevitable Democratic majority for decades to come he's an Atlas folk hero, but now that he's using the same methodologies to arrive at the conclusion of a GOP Senate come 2015 he's now unreliable or along the lines of any other Sabato or Rothenburg type.

Nice move, Atlas.  Nice move.

And I can't wait to see the waterworks here when the GOP gets to 51 on election night.

This place is flooded with Dem hacks? NO!

Literally nothing could be more hackish than predicting Rick Santorum would win in 2006, except possibly if there were Democrats predicting Blanche Lincoln would win in 2010. Are you really in a position to throw stones here?

Anyway, I was never a Nate Silver cultist. He's good at what he does and I respect his work, but he's not infallible.

Yawn. You're boring.

LOL, come on dude, Santorum never led in a single poll and trailed by double digits practically the entire campaign. Insisting he would win is the epitome of hackishness, and I doubt any Democrat on this forum could match it.