What polls can actually tell us

And why they sometimes surprise us in presidential elections.

Polls seem to be dominating the news cycle this US election season, and they’re giving people cause to celebrate or despair depending on how their preferred candidate is faring in them. But if you understand what polls are actually capable of telling you, it might dispel any desire you have for them to predict whether Kamala Harris or Donald Trump will be the next president.

We interviewed pollsters about their processes and explained the basics of how they turn small surveys into a way to measure the entirety of a voting population. No matter what measures pollsters take to make their samples as representative as possible, there’s a limit to how precise they can be. And, sometimes, those same measures can make the poll numbers go awry.

Sources and further reading:

Courtney Kennedy, who we interviewed for this piece and is in the video, co-wrote this helpful primer on how to read election polls:

We interviewed Brian Schaffner, a political scientist at Tufts University, who co-wrote this blog post on weighting polls for this election:

If you want to better understand the polling errors in the 2016 and 2020 elections:

[DGoldy]

In conclusion: The real poll is on November 5th.

[ioriha]

So...morale of the story: Don't trust the polls and just go out and vote.

[sarahj]

I did a phone survey (not about candidates, but about a specific issue) and the guy doing the survey was really excited to find out I was in my mid-20s because we never pick up. I was just really bored that day. 😂

[Jhawk_k]

Theres a very accurate poll coming up that ends on Tuesday

[TWICException]

Younger generations don't answer random phone calls or texts.

[trongnnguyen]

Vox's editing quality is outstanding.

[evanathome]

My poll has Kim Jong Un at 120% chance to win the North Korean Presidency.

[Thomascfd]

As a pollster, this is a an awesome video. Thank you for explaining this better than I ever could

[m-l-]

" What polls can actually tell us", well nothing... actually

[robertopena]

Polling organizations after spending millions and millions of dollars:
"Yeah, this may or may not happen"

[Cajek]

Polls can tell us what boomers who answer random numbers on their cell phones think

[birajguha]

I have worked on polling statistical methods during my PhD days with one of the best pollsters in the country, who sadly passed away in 2019 - there are wayy too many factors to control to use any polling as a predictor - currently pollsters do not account mis-specified strata in the demographics, which is one of the largest sources in error

[FWtravels]

imagine working around the clock spending tons and tons of money only to determine it’s a 50/50 shot that could go either way.

[AliciaSalvadore]

I hope we all know that it doesn't matter who is in the 'top job' because this is a systemic problem -- greed. We have allowed many of our economic sectors, to take advantage of the American people. It's disgusting and frightening for the future of our country. My husband and I will be retiring in the next two years n another country. We are absolutely worried that SSI will no longer be funded. we'll have to rely on his pension, a 403 (b) and a very prolific lnvestment account with my Abby Joseph Cohen my FA. Our national debt is bloating and expanding every month. Our government needs to get spending under control and cut the federal budget.

[ZenithWest]

Lol media made it sound like it was Even showing Kamala having a slight lead... Wasn't even close! As an amateur statistician I am really fascinated about things like this. I see two major possibilities:
(1) Democrats are more likely to respond to the poll
(2) The media making it sound like Kamala is likely to win drove more Republicans to go vote that was on the fence to just be lazy.

[josephbishop]

Well I guess it doesn’t matter anymore 😅

[tetie_]

Don't forget about gerrymandering and in general the awful voting system either, one vote counts more than the other.

[edartis]

This answers my question about why are polls done for only like 500 people for a population of over 300 million. Good video Vox!

[llamaliammm]

the uncertainties are so large its basically created for entertainment value

[sahilmassey]

Population, weighting, sample size, representative sample, all things i learned in school and finally seeing a practical of those concepts here.