It takes extensive work to get around that problem alone, let alone "viral" and other worthless push-polls - work that even the very best in the industry, at the highest level, can make major mistakes on.
But most polls I see are from professional pollsters like Pew or YouGov? For them, correcting for this is opinion polls 101. That's why you see "representative sample". They're not just randomly polling 1000 people and taking the average. They're adjusting for a bunch of other demographic factors as well.
In order to account for that, you need you know how many people who are less likely to respond are voting for that candidate. And then you're back to square one.
This is why professional polls have had a consistent bias over the last few years, as this hidden unobservable factor's effect has gotten stronger and stronger.
Doing a proper poll is expensive and (frankly) most of the time is pretty predictable or you can get 90% of the results with 10% of the effort, and most times you don't actually care about the results because you're building it to get a result you want anyway.
(Interestingly enough elections themselves almost by definition have notable discrepancies to a "true" perfect sampling; but it's usually overcome by the sheer volume.)
If you're trying to do a scientific poll that is not about an election, it can become exponentially harder unless you can find independent ways to obtain data that helps you adjust (like home ownership, which is reported to the government).
I believe this is not true, because at least ESS (European Social Survey) corrects for non-response, although how exactly is beyond my understanding of survey analysis. Each country reports the response rate as well. See [^1] section 3. Although ESS is much larger survey than simple opinion poll, there are political affiliation questions too (`^prtv.*$` variables).
[^1]: https://www.europeansocialsurvey.org/sites/default/files/202...
Sometimes this works out alright. But sometimes not. Too many factors in the universe to model. Never enough power to look at all them even if you knew what they all were. It works well when a few dominant factors are present but when its a million latent factors with technically every pairwise interacting relationship present in some degree, good luck.
Professional polls are either accurate or have a good reason afterwards why they weren’t.
Why not? If they poll the same question (e.g. political party) repeatedly (e.g. in many elections) eventually you could build some kind of model of which parties poll-answerers are more likely to skew towards, or how much they shift compared to non-answerers. Not fundamentally a different process from other ways of removing bias from polls.
There is a lot of public data on past elections that anyone can analyze and see exactly how accurate polls have been in the past. If you're expecting polls to be a perfectly accurate prediction then you are misunderstanding their purpose. What they are great at is giving a probabilistic estimate of the outcome, within a certain range.
It's likely that any key race you care about next week will end up within 4 points of the current polling average. It's extremely likely that it will end up within 8 points. That's useful information!
Yes - they are aware of that.
My point is --> this problem is the most basic and fundamental problem that is the focus of every pollsters existence <--
Asking questions is extremely easy.
Getting a 'truly random sample' is extremely hard.
Trying to factor in those things is 100% of the work, that's what they do, it's their job.
Some are better, some are lazier, some have better data, some are individuals, some are teams so it varies hugely.
When the conditions are controlled they'll have a better idea than otherwise.
Their job is not 'asking questions' it's 'figuring out how to get random samples'.
The entire world works around the legitimacy of authority.
Yes - the quality varies, and pollsters don't have a high degree of institutional authority.
But some do.
If you want to learn about 'institutional legitimacy' - go visilt Pew.
Pew is an extremely well regarded institution. They are extremely good at polling. Go look at their methods.
They are a long running institution with serious professionals, big budgets, people who really know waht they are talkinga bout.
It's the difference between getting diagnosis from 'a neighbour' vs a 'doctor' but in this case there is no specific qualification.
Some 'respected pollsters' are basically insiders who have been doing it for a long time, with relationships and credibility - others, more institutional.
Check out Pew, they are probably he closest thing to institutional professional as possible.
Political polling is inherently hard - they will be the first to admit.
When they are 3 or 4 percentage points off they are ripped to shreds.
The polls for the recent Brazil elections were about 49% for Lula, the result was 52%, that's a 3 point difference, not a massive error margin. With brexit the polling pointed to about 52% for remain, actual result was 48%.
But those are proper polling companies, not worthless online ones.
Do you have one example of a poll that isn't?