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Apr 10, 2024 17 min

How much does this cow weigh? (Classic)

from Planet Money

This episode originally ran in 2015. About one hundred years ago, a scientist and statistician named Francis Galston came upon an opportunity to test how well regular people were at answering a question. He was at a fair where lots of people were guessing the weight of an ox, so he decided to take the average of all their guesses and compare it to the correct answer. What he found shocked him. The average of their guesses was almost exactly accurate. The crowd was off by just one pound. This eerie phenomenon—this idea that the crowd is right—drives everything from the stock market to the price of orange juice. So, we decided to test it for ourselves. We asked Planet Money listeners to guess the weight of a cow. Spoiler: You can see the results here. This episode was hosted by David Kestenbaum and Jacob Goldstein. It was produced by Nadia Wilson and edited by Bryant Urstadt. Alex Goldmark is Planet Money's executive producer. Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney. NPR Privacy Policy

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How much does this cow weigh? (Classic)

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Every episode of It's Been A Minute, MBR's What's Happening in Culture Podcast starts by asking three questions. Who? How? Why now?

If the culture's asking it, we're talking about it. At MBR, we stand for your right to be curious and indulge your cultural curiosity. Follow It's Been A Minute Where You Get Your Podcasts. We'll break down the zeitgeist topics that are filling your feed.

This is Planet Money from NPR. Hey everyone, it's Erica Barris, the show you're gonna hear today originally aired in 2015. Here's Jacob Goldstein and David Castanbaum. Francis Galton was the kind of person who believes in experts.

You know, people who had studied things, people who knew stuff. He figured they knew things that ordinary people just did not. I mean, of course they did, right? Obviously.

Alinda A. Galton goes to a country fair. This is about 100 years ago in England. And there's this contest going on at the fair.

Guess the weight of the ox. Galton's a scientist and a statistician. And he figures, hey, I can do an experiment here, right? He figures, I'm gonna take everyone's guesses, take the average, and compare that to the actual weight of the ox.

We heard the story from James Sir Wicky. He's an economic journalist. So he thought what you were gonna end up with was a really flawed guess. Because in his mind, what you were doing was, you were taking guesses of a few smart people, a few mediocre people, and then a lot of morons.

Because he basically cut everyone's guess. So he figured the group's guess was gonna be way, way off the mark. The contest organizers gave Galton the little slips of paper with everyone's guesses on him. He took him, calculated the average.

The average was 1197 pounds. And the ox? The ox weighed 1198 pounds. So that in other words, the crowd's judgment was essentially perfect.

One pound off. One pound off. This is super creepy. What's going on?

There's some kind of collective unconscious magic. It's like a Ouija board or something, right? But the idea that underlies this, it is everywhere. It's the idea of the stock market.

You know, thousands of random people buying and selling shares. Like when you hear that Apple stock went up, or the Dow plunged. That's basically people guessing the weight of an ox. Yeah, it's everywhere, right?

It's the price of oil. It's the price of orange juice. All kinds of things that are really important to the world work exactly this way. But why should it work?

Why should a bunch of random people, a lot of whom have no idea what they're doing, somehow magically produce an answer that makes sense? Does this really work? And if it does, why does it work? Hello and welcome to Planet Money.

I'm Jake McGolstin. And I'm David Kestenbaum. Today on the show, Mr. Galton, we redo your experiment.

What's the cow's name? Penelope. Hi Penelope. Thanks for letting us weigh you.

Can I pet her? Yeah. She's chewing. One pound off.

Come on. NPR's newest podcast is where you can find NPR's biggest interviews. I'm Steve Ensky. The program is called Newsmakers.

We talk with some of the most powerful and influential people at this moment to put real questions to them and push for real answers. Follow Newsmakers on the NPR app or any podcast player or you can watch on NPR's YouTube channel. So we came up with a plan to repeat Galton's experiment. Find a fair and a cow and a big scale to weigh the cow.

And then... Secret and secret. And then we were going to throw the question out to the crowd, ask the world, how much does this cow weigh? We didn't want to just limit it to people at the fair.

So we figured we'd take some pictures, post them online, and ask the whole world to guess. So we went out to a county fair in Burlington County, New Jersey. We met Penelope the cow in the dairy tent. She was sitting on a bunch of hay.

Kirsten Kuzmitz was taking care of her. Can you just describe what she looks like? Yeah, she's mostly black. She has white legs and she has a white spot in the middle of her head, but she's a big black cow.

What did you just say? I said, I said, I said, I only cow without even realizing what I was saying. She's much bigger. She just stood up.

She's walking out of the barn now. And she's way bigger than I thought when she was sitting down. We took some pictures of you Jacob standing next to the cow for scale. And just for fun we decided to ask people to fare how much they thought they'll be waiting.

It doesn't happen, it was kids day, so there are a lot of kids right? Hi Penelope. Which was fine, you know, they're non-experts. What's your name?

Caleb. How much do you think? An LP was? Uh, six pounds.

How'd you come up with that number? Because I'm six years old. You guys want to get so much of this cowways? 6,600 pounds.

Like 6,000. Yes. Do you know how much you went? Not at all.

I'm sympathetic. Looking up at LP, I had no idea how much she waits. Like I didn't even know how to think about it. Did she wait more than my car?

Did she wait less than my car? I don't even know how much my car waits. More than a cow. I'm just saying more than a cow.

We found an older group of kids and yeah, they also guessed on the low side, but they had this bigger problem, this really more worrying thing. And it was a problem that adults also seem to have. And it was this. The first kid said a number.

And then all the other kids said, basically the same number. Numbers that were like too close to the first kid. It's like they're incapable of guessing anything different. My name's Yissa.

And Yissa, how old are you? I'm on 10. How much do you think that cow weighs? Um, 200 pounds.

My name's Gabriella, I'm 10. And I think the cow weighs 300 pounds. My name is Kid, I'm a nine, seven years old. And I think the cow weighs 300 pounds.

Okay. People are not that different from cows. We heard. If we don't know something, we look for a leader, even if the leader maybe doesn't know anything.

To not be finished chewing, and we took her over to be weighed. It's actually pretty unusual to want to weigh a cow. And the scale they had at the fair was not for cows. What kind of scale is this?

It's actually like a truck scale is what it's for. Same size scale I'll use for big trucks and stuff. Which we use it to weigh the trackers during the tractor pool. It'll work for a cow.

Yep. Testing them, you were obsessed, paranoid, arguably paranoid about keeping the result of this secret. You didn't want it to leak out, I guess. Can all these people have gathered?

Actually, can we seriously clear everything out except for just the minimum of people? Can we swear you to secret? Okay, just everything else over there. Kirsten walked Penelope up onto the scale.

Can we watch this little digital display? Oh. 1,355 pounds. That's pretty good.

1,355 pounds. We walked Penelope back to the dairy tent, and then we went home. The next day we posted photos online of the cow and you. And me, right.

I was there to give some sense of perspective. We put you on the tractor scale. Yes, 165 pounds. That's how much I weigh.

Then our colleague, Kwok-Tram-Booey, put it all up online. Guess the weight of this cow. And the idea was our hope was that lots and lots of people would guess because the fundamental question here, the thing we're trying to figure out is if you have a bunch of random people making their best guess at something, do you get close to, you know, the truth? Do you get close to the right answer?

So we put it up and we waited for the results to come in. All right, it's been up for how long now? Two minutes. How many entries?

Uh, it's 15 entries. Reload, reload. All right, here we go. Still 15?

Still 15. Come on. Oh my God. That's all we're going to get, 15.

We're going to retweet this. You're sorry, I've been buried after two minutes. No. We also show the pictures of me and the cow to James Swicki.

He's the New Yorker writer we talked with at the beginning of the show. He actually wrote a book called The Wisdom of Crowds. So we asked him to guess. Remember here the actual weight of the cow?

1,355 pounds. All right, I will guess that the cow weighs 725 pounds. How did you come up with that number? Ah, I don't know.

Maybe it looks like four, five times, Jacob's size, I guess. I'm sure cows are, I don't know. Are they denser or not than humans? So, you know, whatever.

It's pretty random, actually. Pretty random and pretty wrong. We told them Penelope's actual weight twice as heavy as his guess. It's so bad.

It's a sad commentary that someone's been talking about in Oxford. This long has absolutely no clue how much a cow weighs. We get a crowd of people like you. It's going to be terrible.

We're going to be in bad shape. I'm praying somebody was guessing 2200 on the other end. Because the key question is what the average is going to be, right? Is the crowd going to get it right?

Or at least how close are they going to get? So we left this up online for five days. Let people guess for five days. Our colleague Boi tallied it all up.

David, you and I came into the studio. We didn't know the results. And Boi came in to give us the numbers. First of all, how many people guessed?

So the number of people I guessed. 17,205 people. 17,000? That's legit.

That's good. That's good. It's as if you got like a small town to all guesses. Boi took those guesses, added them up and calculated the average.

This was the big moment. You guys ready? 1,287 pounds. 1,287.

Penelope actually weighed 1,355. Pretty close, right? So that's to within like what 60ish pounds? That was pretty impressive.

Yeah, I mean, they're only like 5% off. You know? And okay, sure, the Galton thing was one pound off. They season that.

But remember, this is just a bunch of random people, you know, looking at this little tow picture in their Facebook feed on their iPhone. And here's another amazing thing. When we asked people to guess, we also asked them this other question. We asked, are you an expert?

Have you ever worked with cows? Because remember, Galton thought experts might be better. And 3,000 some people answered yes to that question. Jacob, you wondered where they really, really expert.

These are just people clicking a button online. So we emailed a bunch of them and we heard back and they did seem pretty expert. You know, a lot of them were farmers. One of them mentioned the quote absence of a visible utter.

Actually, a few of them mentioned it. And apparently that tells you some about how old the cow is, how much it weighs. So how did the experts do? Here's the answer.

So the average guess for the experts was 1,272 pounds. They were worse. They were worse. It's amazing.

So okay, so maybe that is wisdom of the crowds. To be fair, the experts were only marginally worse. But they did not beat the crowd. We told Sir Wiggy about these results and he wasn't surprised.

In fact, he writes in his book, chasing the expert is a mistake. We should ask the crowd. And the fact that the larger crowd got it to within 5%. He said that seems about right to him.

When people do versions of this experiment, asking people to guess the number of jelly beans in a jar, for instance, the crowd usually gets it within 3% to 5%. One of the things interesting about this is even though I've written the book and done this experiment a number of times, every time I do it and every time I hear the results, I'm like, it's not going to work this time. Because the idea is so counterintuitive. You know, it's pretty extraordinary in that regard.

The power of this to actually let the group arrive at really good decisions is it's eerie. There's something eerie about it, I think. It is eerie, right? Yeah, it is.

There's something magical about it that seems magical, I think. It's not magic. It's just math, but it seems magical. Sir Wiggy says the reason this seems to work is that every person's guess is contributing some new little piece of information.

Everybody is different. Everybody thinks slightly differently when they're trying to guess the cow's weight. Maybe one person studies that photo of the cow from the side. Some people are probably trying to figure out how many Jacob's would fit in the cow.

Someone else might know how much a horse weighs and kind of go from there. Like every person's guess in some ways reflects their specific life experience of judging the size of things in the world, just from decades of living. It's like every person's mind is a different scale for weighing the cow. Anyone of those scales isn't going to be a great scale, right?

Each one of those is probably going to be wrong. There's going to be some error in every single one. They're good in some way, but they also have some problem with them. Yeah, and one of the essential things is those problems tend to cancel each other out, right?

Maybe one person is wrong, 200 pounds high, but the next guy is wrong, 200 pounds low. So the wrong part, the wrongness kind of washes out. And in the end, what you're left with is all those little bits of information. And the result is amazingly good.

You know, collectively we do seem to know what we're doing. Sir Wiggy says there are certainly times when this does not work. Like think stock market panics or bubbles. Yeah, a big problem is that thing we saw with the kids at the beginning, where one person says a number and everybody else around them just kind of latches onto that number.

There's actually a technical term for this. It's information cascade. It's like my neighbor just bought a house. That seems like a lot of money pay for a house, but he did fine.

I'm going to do the same thing. Or everyone's buying that stock. It must be a good stock. I'm going to buy it.

The stock market is not perfect. But what is amazing about the stock market is that investors, individually, even very good investors, are oftentimes irrational. They have tiny bits of information. They're making decisions based on emotion or on, you know, some tip they got.

And yet collectively we trust them to set the value of all of these companies. It's kind of scary when you think about it. But the interesting thing is that I don't think there's a better way to do it. And it's not a more effective way of doing it either.

This is why it is so hard to beat the stock market. The wisdom of the crowd is pretty good. And the people who seem to be there who say, I can beat the stock market. Often they are just plain lucky.

In our experiment, for example, there were 15 people who got the cows weight exactly right. They were off by zero pounds. We picked one of them at random as our winner. We called them up to tell them the news and to see how he did it.

Hello. This is Harris. Yeah. How's it going?

Harris Pollock is 20 years old. He's a student at Hamilton College never touched a cow in his life. In fact, could not even remember his guess. We told him he'd guessed 1,355 pounds and that the weight of the cow was also 1,300.

55 pounds. Oh my God. You won. That's amazing.

You want to know how he got to that guy? Yes. I Googled it by Google's average weight of female cow and it said, here I'll get it. So it pops up in a little box and it comes from dairymoosedairymos.com.

Dairymoose.com says average weight of a cow is 1,500 pounds depending on the age and whatever. Harris looked at the picture of Penelope the cow and said, she looks a little bit on the small side. He went with 1355. Who's just a guess?

Yeah, completely guess. So we're going to send you the cheapest plastic cow trophy we can find. We talked to the Harris about what we should put on the trophy because it's a bit of a puzzle, right? Like should it say, I got lucky?

He was actually fine with that. He said that made sense. I was pushing for mutual fund manager of the year. Robert, you suggested someone had to win.

In the end, I think we are just going to say congratulations. Congratulations. The surreal horror film Back Rooms is a smash. The director is a 20 year old YouTuber and it's based on his popular web series.

Why is this online phenomenon taking off of the box office? We get into it on NPR's Pop Culture Happy Hour. Listen via the NPR app or wherever you get your podcasts. All right, we got some footnotes.

You know how at the end of research papers, they put all the technical details there? A couple of things we want to tell you. When we calculated the average of the guesses, we did throw out outliers like the person who just held down the nine key as they're guess. 9999999999999.

Thanks for that. Also for people who love the median, we calculated the median too. I am a median lover. The median is the value in the middle where half the guesses are higher, half the guesses are lower.

The median was pretty close to the average. The median was 1,245 pounds within 8% of Penelope's actual weight. The median expert guess was a little worse but pretty close. You can find all the numbers online at npr.org slash money.

Also, there are some pictures of Penelope the Cow, among other things on our Instagram feed at Planet Money. You can also email us on at money at npr.org. Thank you also to everybody for guessing. Thank you to Penelope the Cow and to Rosemary Kay and the other folks at the Burlington County Farm Fair.

This episode was originally produced by Nadia Wilson, and today's rerun was produced by Liza Yeager and Rachel Cohn, with additional audio support by Valentina Rodriguez Sanchez. Ryan Erstadt edited this episode. Alice Goldmark is our executive producer. America Bares, this is NPR.

Thanks for listening. How heavy is it, Count? Absolutely no idea. Absolutely no idea.

I really wouldn't. Like is 10,000 pounds sound too heavy or who knows? Uh, I really have no idea. 20,000 pounds?

20,000 I think is going over the limit. Yeah, no. So less than 20,000. Less than 20,000?

More than five pounds. More than five pounds. Yeah, more than a bird. This week on NPR's Newsmakers, main Senate candidate Graham Plattner, a working class Democrat leaning into one message that the political system is rigged to favor the wealthy.

There's only one direction. We need to be pointing fingers and that is up. It's not left and right. Can that message help Democrats take the Senate in this year's midterms?

Graham Plattner, this week on NPR's Newsmakers. Watch or listen wherever you get podcasts.

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