> There is no reason that polls would be significantly different from the final vote results in most circumstances, if they are competently run.

There is lots of reason.

If you could wave your magic wand and get a representative sample of voters in your poll you would be right, but you can't. Instead you do something like call people on a telephone, get a sample of people who both answer the telephone and who give answers you think indicate they are likely to vote. That sample isn't going to be at all representative of the voting population, so you take your best guess at what the actual voting population looks like, and how representative each of the people in your sample is of the voting population, and weight it accordingly.

Your best guess at the actual voting population is probably wrong. Your best guess at how representative each person in your sample is of the actual voting population is wrong. Your doing things like assuming that every <race> person with <education level> votes similarly regardless of whether or not they answer the telephone and respond to pollsters because you really just don't have a better option.

Then why are they repeated ad nauseam?

Polling is hard and the result are likely non-representative. Great! Then don’t display them to the public and have pollsters in interviews acting as if their insight is in any way valuable to most people. They’re either incompetently wrong or, worse, intentionally manipulative.

Just because something exists doesn’t mean it has value in the wrong context.

Just because something isn't perfect doesn't mean it has no value. Polls communicate experts best guess at how the vote is going to turn out based on the data they have collected. It's likely to be a lot more accurate than a non-experts guess, or even the guess of an expert without any data. It's also not even possible to share the raw data because of privacy concerns.

The forecasts you see on sites like 538 and the economist are even better, because it doesn't just communicate experts best guess (democrats win by +7), but experts best guess at how accurate that guess is too (something like democrats win by +7 +- 6, except in a lot more detail and nuance).

On HN the catchphrase for this is basically "don't let perfect be the enemy of good".

Note: I made up the numbers in this post.

@gpm what I’m arguing isn’t for replacing good with perfect. I’m saying these don’t make it to the level of good. They provide no relevant or valuable information to the public.

If weather forecasters were wrong nearly 100% of the time, would they provide value? If a hurricane was approaching and they couldn’t predict probable paths within any margin of error, would they provide any value.

If a weather forecaster can predict the temperature next week to within a few degrees and can tell you when they are sure it will rain, when they are sure it will be sunny, and provide a good guess as to rain or shine on most of the other days you would consider that person a good weather forecaster.

Do you expect the weather report for the next week to nail the temperature of every day next week to within 1 degree?

The pollsters can tell you if a hurricane is coming, they can tell you when the weather might shift significantly (albeit not be absolutely certain about which direction it is shifting) and they can give you a very good idea of what to expect even if they do not get the exact temp for each day correct.

really though, what tangible value do polls provide anyway? i get that the polling over the last few years hasn't been great, but i don't really understand why everyone's so upset about it. did anyone actually make or change decisions based on these polls? they're just predictions anyway.

for instance, in your example, a hurricane's path directly affects citizens of cities that lie on that path—do they need to prepare to leave their homes, etc.? but is anyone actually basing their decision to vote or who to vote for on the polls in such a way that it significantly affects the outcome?

> what tangible value do polls provide anyway

I live in Canada but am working for an American country. I am considering if/when I want to move to the US, they informed me about the likely outcome of this election, which influenced my plans a non trivial amount (not a huge amount either, covid dominates in the planning process, but a non-zero amount).

For many people it can influence how they vote. If you're in a state with a potential to change the outcome of the election you are more likely to vote "strategically", i.e. vote for one of the two most popular candidates instead of vote for a third party that you prefer. On the flip side if you're voting in a non-competitive race you are much more likely to vote for a candidate who is unlikely to win in order to better indicate your preferences (i.e. you should be more likely to vote libertarian/green/...).

For many people who wins an election affects there careers going forward, in the US in particular a large number of people are fired/hired based on the election. Even if you're not in that position your industry might get more or less government funding, if you're a government contractor the projects you are working on might or might not be in danger of getting cancelled, and so on and so forth. Having better information earlier makes it easier to plan your life.

The US election is one of the most significant worldwide events that happens every 4 years, the idea that being able to better predict it is not valuable is... insane.

you definitely make some good points. i realized a few things i didn't think about after posting as well.

i guess i was thinking more along the lines of, most of the time i personally don't think you should be choosing a presidential candidate based on predictions of who may or may not win. even some of your examples are more centered on the ultimate outcome of the election and how to plan for it; i really think people whose lives could be affected that drastically should be planning ahead for that situation anyway.

nonetheless, i agree they do have some value, and perhaps i should have clarified my line of thinking more clearly.

I think it's clear that people being polled are not representative of those who are voting. Trump has eother managed to appeal to people resistant to being polled or has managed to disengage people that are being polled. Whatever your views on the man, it's remarkable.

What's more surprising to me is that he can do it consistently and that no one has seemingly appealed to these people before. Given that these are almost election winning demographics, it's odd that no one has spent more time on understanding these people.

You obviously have no understanding of either polling or statistics. This is like saying that if computer programmers were not incompetent we would not have bugs in programs, but since they all obviously do not know what they are doing we have a modern society held together with chewing gum and string because programmers are too dumb to get it right.

What does "competent" mean if none is competent? Are engineers incompetent because they can't put a person on Mars?

Sure, if some engineers told you "we are putting this person on Mars with a 99.9 probability", and the rocket in fact reaches Venus, the engineers are incompetent.

Also, polling in most European countries doesn't go this far wrong, on almost all polls. So it's not like "accurate polling is impossible", it's just the polls in the US that seem to have some problem (though there have been some spectacular failures in other countries as well, which itself may lead to some thoughts on the value of polls in general).

> polling in most European countries doesn't go this far wrong, on almost all polls.

Brexit and UK elections would like to have a word with you...

Polling everywhere sucks. Pick a country and chances are it either has no polling to speak of or else it has the same problems.

YouGov are pretty good, mostly because they grew up in the Internet Age.

But I agree with your general point.

It's not within the normal margin of how off polling averages tend to be. (Though every once in a while you'll get an abnormal miss)

But it is definitely within the margin of error for many individual polls, which often have a MoE > 2.5%.