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Sat Nov 5, 2016, 06:04 PM

The Fundamental Problem with Nate Silver's Model

The fundamental problem with Nate Silver’s model is that the state polls cannot be reconciled with the national trend. You cannot have states like NY, CA, WA up 20 points, another dozen states where Clinton is up 15 points and the most populous red states like TX, AZ and Florida where she is even or down just a little and then have the national polls where Clinton is only up 3%, it just doesn’t add up.

EITHER HUNDREDS OF STATE POLLS ARE WAY OFF OR A FEW NATIONAL POLLS ARE A FEW POINTS OFF. SILVER HAS DECIDED THAT THE NATIONAL POLLS ARE GOLD AND ADJUSTS DOZENS OF STATE POLLS IN ORDER TO MAKE A SQUARE PEG FIT A ROUND HOLE.

The Princeton consortium never uses the national polls as the state polls are much more accurate and they don’t have to adjust to make them fit

Silver’s model is based on his sports models where there is a constant stream of games being played on schedule with a set data stream. One of the problems with the last 2 weeks of the election season is that Republicans launch a barrage of polls from RW pollsters (who ever heard of Remington?) that lean heavy Republican that are used to help with their GOTV.

Silver’s top down approach that gives preeminence to national polls is not as stable as the bottom up approach that other sites use that work on a larger and more accurate base of state polls. If you accept that Clinton is currently 6% ahead nationally then you can reconcile all of the state polls without major adjustment.

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Arrow 15 replies Author Time Post
Reply The Fundamental Problem with Nate Silver's Model (Original post)
grantcart Nov 2016 OP
manicraven Nov 2016 #1
grantcart Nov 2016 #4
Avalux Nov 2016 #2
Hortensis Nov 2016 #3
DLCWIdem Nov 2016 #6
grantcart Nov 2016 #7
GopherGal Nov 2016 #16
yardwork Nov 2016 #8
Awsi Dooger Nov 2016 #9
grantcart Nov 2016 #10
BzaDem Nov 2016 #11
pnwmom Nov 2016 #15
Cha Nov 2016 #12
grantcart Nov 2016 #13
Cha Nov 2016 #14

Response to grantcart (Original post)

Sat Nov 5, 2016, 06:16 PM

1. Spot on!

The fundamental problem with Nate Silver’s model is that the state polls cannot be reconciled with the national trend.


That makes sense!

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Response to manicraven (Reply #1)

Sat Nov 5, 2016, 06:46 PM

4. Thats a great picture.

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Response to grantcart (Original post)

Sat Nov 5, 2016, 06:19 PM

2. Thank you for this concise explanation!

I agree - he's got it backwards.

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Response to grantcart (Original post)

Sat Nov 5, 2016, 06:24 PM

3. Love the conclusion. I've seen a number of people say

national polls are mostly bogus at this point and that state polls are far more reliable. Also that the best are the extremely well funded internal polls of both candidates--algorhithms fed with vast amounts of information they've been gathering about voters, right down to what kind of underwear they prefer if believed relevant.

Come to think of it, that's a correlation that would be fun to check out.

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Response to grantcart (Original post)

Sat Nov 5, 2016, 07:30 PM

6. HOW about early vote. How does that for in

Does Nate' s model look at early vote at all?

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Response to DLCWIdem (Reply #6)

Sat Nov 5, 2016, 11:02 PM

7. He doesn't factor that in. And it doesn't make sense either


NV has a huge D lead and he still has it Red.

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Response to DLCWIdem (Reply #6)

Sun Nov 6, 2016, 09:46 AM

16. Doesn't explicitly include early vote

But his model prefers poll results for "likely voters". I don't know how that works within the polls themselves, but I would think that if there's an "already voted" category that boosts respondents' scores in "likely voter" weighting, the polls themselves (rather than the aggregation model) might be indirectly accounting for the early vote.

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Response to grantcart (Original post)

Sat Nov 5, 2016, 11:05 PM

8. So glad to see your posts again!

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Response to grantcart (Original post)

Sat Nov 5, 2016, 11:22 PM

9. Sorry, the state polls make no sense in relation to a 6 point Hillary lead

Not even close. They are much more in line with a 3 point national advantage.

For example, if Hillary leads nationally by 6 points but her Pennsylvania edge is 4-5 points, then you're trying to tell me Pennsylvania has a slight red tilt. The states you picked are not in play. No advertising blitz. The margins can shift considerably in situations like that from cycle to cycle. Republicans used to contest Washington state more than they do now, so naturally the blue edge can rise.

I've used the partisan index for 20 years and used to post the statewide numbers here more than a decade ago, before it was widespread to do so.

Keep in mind that this cycle is challenging from a partisan index perspective because Trump has unusual strength in states with high percentage of whites but not as many Hispanics or blacks than other swing states. The partisan index in states like Ohio and especially Iowa figures to shift into territory we haven't seen before, at least not recently. Those states may also move against us in general, similar to states like West Virginia and Missouri over the past 15 years or so.

Many states are in partisan index flux currently. Quite interesting. Most in our favor but some of them are still Hail Mary caliber, like Arizona and Georgia and Texas.


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Response to Awsi Dooger (Reply #9)

Sat Nov 5, 2016, 11:34 PM

10. Absolute nonsense


You are only quoting the polls in the swing states

California +22
New York + 20
Mass + 22
Washington, Maine, Conn, Deleware, IL Hawaii, MD, VT all around +15

On the Republican side you have a lot of low populations states that have wide margins but their large states are very narrow margins

Texas -9
AZ - 5

and a whole bunch of Atlantic states that have been red but are now tied or blue
Virginia
North Carolina
Florida
Georgia

Its not really a point of contention. Silver explicitly states that he is moving the state polls by 3 points so that they mesh with the national numbers. He has a term for it, he calls it "trend line adjustment".

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Response to grantcart (Original post)

Sat Nov 5, 2016, 11:37 PM

11. His model is mostly based on state polls.

He does use the national polls to adjust state polls, but he says that only 10-20% of the uncertainty comes from that. He says the other 80-90% comes from other factors (larger than normal undecided/third-party factor, higher variability in the polls, correlations between states, etc.)

He also said that if the national polls all uniformly ticked up a point, his model would show Trump as still having a 25-30% chance of winning.

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Response to BzaDem (Reply #11)

Sun Nov 6, 2016, 05:10 AM

15. How Nate Silver "unskews" the polls -- and why he shouldn't.

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Response to grantcart (Original post)

Sat Nov 5, 2016, 11:40 PM

12. Mahalo, grant! This is kind of what I was gathering from reading

what was being said about Nate's models and Sam Wang's methods.

Just saw this tweet from Sam..

Sam Wang ‏@SamWangPhD · 6h6 hours ago
Sam Wang Retweeted Clara Jeffery
Good thing there isn't anything serious to do, like figure out what's happening in Senate, or interpret early voting, or go get out the vote

https://twitter.com/SamWangPhD?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Eauthor

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Response to Cha (Reply #12)

Sun Nov 6, 2016, 04:57 AM

13. Hey Cha

Here is something to think about

With the enhanced Hispanic turnout I wonder if in the Southern States with large Hispanic population that we may do better in the house than people are thinking about. Maybe 20+ seats.

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Response to grantcart (Reply #13)

Sun Nov 6, 2016, 05:05 AM

14. Good point! And, considering Team Hillary's ground game, too

tephanie ‎@FormasForever
Listen, there is no ground game better than @HillaryforPA. By 6 PM, our vols knocked on 621,720 doors. That's 69,080 an hour. #proudtobePA
2:44 PM - 5 Nov 2016
72 72 Retweets 100 100 likes

https://twitter.com/FormasForever?ref_src=twsrc%5Etfw

Good to see you back

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