Also, to be clear, in order to compute his prediction, Wang did assume that non-sampling errors were somewhat correlated, just not nearly enough. As I say in the post, he is a very smart guy, so it’s not as if he didn’t know the things I explain.
phl43
Karma: 48
A question about the rules
To be clear, this is just a random thought I had as I was reading Drescher’s book, I’m really not sure there is anything particularly deep or even interesting about it.
What a Portuguese chronicler may teach us about moral relativism
I agree with you that the probabilities of Clinton winning individual states are correlated, but I’m not sure this makes what I wrote false, although you’re probably right that it’s a bit misleading. The fact that the probabilities of Clinton winning individual states are correlated is only relevant to calculate the probabilities for each possible outcome in the electoral college. It means that, as I explain later in my post, you have to take into account the fact that non-sampling polling errors in different states are correlated in order to calculate the probabilities for each possible outcome in the electoral college. One of the sources of non-sampling error that I describe in my post is measurement error, which if you read my post carefully I define in such a way that if someone doesn’t vote for the candidate they claimed they would vote for when they participated to a survey for whatever reason (e. g. because they heard a news story that made Clinton or Trump look bad), it counts as measurement error. I agree that it’s probably an unusual definition of this concept, which is typically construed more narrowly. But I defined measurement error in that unusually broad way precisely because I didn’t want to introduce the complication that, even if someone who tells a pollster n days before the election that he’s going to vote for X and would really vote for X if the election took place on the day he participated to that survey, he might not vote for X on election day. (Wang takes that, among other things, into account in order to calculate his prediction, but I was only describing the way in which he calculates a snapshot of where the race stands at any given time, since I think it’s where the most interesting mistakes were made. I may be wrong about that, but judging by what he said after the election, I think Wang would agree with me on that.) Now, if the probabilities you calculated for each possible outcome in the electoral college are correct, then you can just use the aggregation method I describe above the passage you quoted in my post. What is misleading in my post is that I say the assumption for that method to be reliable is that the probabilities of Clinton winning individual states are correct (instead of the probabilities for each possible outcome in the electoral college), because it suggests that we can assume they are probabilistically independent (although I never said that and the rest of my post makes clear that I wasn’t making that assumption), which of course they are not. Do you agree with that or do you think that there is a more serious problem here?
I think models that rely on fundamentals are worthless. I don’t have time to explain why in details, though perhaps I will post something on that at some point, but if you want to know the gist of my argument, it’s that models of that kind are massively underdetermined by the evidence.
Oh I see. I had totally missed the fact that it was a reply to another comment. Apologies to tgb.
I’m not sure you have read my post. Nowhere in it do I say that we should have focused on one poll rather than another. So I’m not sure what relevance your comment has.
I’m sure pollsters sometimes “cheat” by constructing biased samples, but this can happen even if you’re honest because, as I explain in my post, polling is really difficult to do. To my mind, the problem had more to do with commentators who were making mistaken inferences based on the polls, than with the polls themselves, although evidently some of them got things badly wrong.
Why election models didn’t predict Trump’s victory — A primer on how polls and election models work
Did slavery make the US an economic superpower and would the industrial revolution have happened without it?
Okay, thanks, I’ll try that.
I just tried to post a link to the one about slavery and capitalism, but it remains a draft and I don’t know how to actually publish it. Any idea what’s going on?
Thanks! That’s a good idea, I’ll do that shortly, starting with the post about slavery and capitalism.
A new blog with analyses of various topics (e. g. slavery and capitalism, why election models didn’t predict Trump’s victory)
Thanks, I’m reposting it.
Hi everyone,
I’m a PhD candidate at Cornell, where I work on logic and philosophy of science. I learned about Less Wrong from Slate Star Codex and someone I used to date told me she really liked it. I recently started a blog where I plan to post my thoughts about random topics: http://necpluribusimpar.net. For instance, I wrote a post (http://necpluribusimpar.net/slavery-and-capitalism/) against the widely held but false belief that much of the US wealth derives from slavery and that without slavery the industrial revolution wouldn’t have happened, as well as another (http://necpluribusimpar.net/election-models-not-predict-trumps-victory/) in which I explain how election models work and why they didn’t predict Trump’s victory. I think members of Less Wrong will find my blog interesting or, at least, that’s what I hope. I welcome any criticisms, suggestions, etc. Sorry for the shameless self-promotion, but I just started the blog and I would like people to know about it :-)
Philippe
Hi everyone,
I’m a PhD candidate at Cornell, where I work on logic and philosophy of science. I learned about Less Wrong from Slate Star Codex and someone I used to date told me she really liked it. I recently started a blog where I plan to post my thoughts about random topics: http://necpluribusimpar.net. For instance, I wrote a post (http://necpluribusimpar.net/slavery-and-capitalism/) against the widely held but false belief that much of the US wealth derives from slavery and that without slavery the industrial revolution wouldn’t have happened, as well as another (http://necpluribusimpar.net/election-models-not-predict-trumps-victory/) in which I explain how election models work and why they didn’t predict Trump’s victory. I think members of Less Wrong will find my blog interesting or, at least, that’s what I hope. I welcome any criticisms, suggestions, etc.
Philippe
Okay, I honestly don’t really care about this particular incident, I just want to know the rules so I don’t violate them again. I hope someone in charge can explain to me.