How purchasing power parity compares costs between countries

HostWhen we think about how rich or poor a country is, we usually just look at the total amount of money they make and change it all into dollars to compare them. But that doesn't really tell us what it's like to actually live there or what a paycheck can really buy at the local store. How do we actually measure what money is worth when the price of a basic loaf of bread changes the moment you cross a border?

GuestIt's a huge puzzle for anyone trying to understand the global economy. Most people just look at the exchange rate, you know, the number you see at the airport or on a banking app. If one dollar gets you one hundred of some other currency, you might think you know what that money is worth. But that exchange rate only tells you what the money is worth to a bank or a big trader. It doesn't tell you how many eggs or shirts it buys. To get the real picture, we use something called purchasing power parity. The basic idea is to stop looking at the coins and start looking at the stuff. We imagine a giant shopping basket filled with the same everyday items in every country, things like bread, milk, a pair of jeans, and a haircut. Then we ask, how much of the local money does it take to buy this exact basket here versus there?

HostBut if I can see that a pair of jeans is way cheaper in another country, wouldn't people just buy them all there and ship them back home to sell for a profit? I would think that eventually, all these prices would just even out.

GuestWell, for things like jeans or laptops, that does happen to some extent. If a computer is half price in one country, big companies will buy them there, and that trade tends to push the prices closer together over time. We call that the law of one price. But the catch is that a lot of things in our shopping basket can’t be put on a boat or a plane. You can’t ship a haircut from Thailand to New York. You can’t ship a doctor’s visit or a month of rent or a gym membership. These are services, and their price is mostly based on the cost of local labor. In a country where wages are lower, that haircut is going to be much cheaper, even if the barber is using the same scissors and the same skill as a barber in a rich city. This is why your dollar seems to stretch so much further in some places. The money goes further because you're paying for the time of people who earn less.

HostSo the official exchange rate might say a person in a developing country makes two dollars a day, but that sounds like it would be impossible to survive. Does this way of measuring things change how we see poverty?

GuestIt changes it completely. If you only look at the exchange rate, a huge part of the world looks like they're living on almost nothing. But when you use this basket of goods method, you see that those two dollars might buy as much food or housing as ten or fifteen dollars would in the United States. It doesn’t mean they're rich, but it means they aren’t as close to the edge as the raw numbers suggest. Organizations like the World Bank use this to set the global poverty line. They want to know if someone can afford the calories they need to stay healthy, not just how many dollars they have in their pocket. If we didn't account for these price differences, our map of who's struggling would be totally wrong.

HostI can see why it's useful, but it feels a bit flawed. How do you even decide what goes in the basket? People in Tokyo aren't buying the same things as people in a small town in Brazil. If the baskets are different, how can the comparison be fair?

GuestThat's the biggest headache with this whole system. It's very hard to compare a basket of goods in two places that have different cultures. In one country, everyone might eat rice and beans, while in another, they eat wheat and cheese. If you put cheese in the basket for a country that doesn't really produce it, the price will look incredibly high, but it doesn't matter because no one there's buying it anyway. To make it work, researchers have to find things that are pretty much the same everywhere. That's actually why the Big Mac became such a famous way to explain this. It's a very specific product made with the same ingredients and the same process in almost every country. If a burger costs five dollars in Chicago and two dollars in Kuala Lumpur, it gives you a quick, dirty way to see that the local currency in Malaysia can buy a lot more than the exchange rate suggests.

HostSo it’s less about a perfect list and more about finding a common yardstick.

GuestExactly, but even with a good yardstick, things change. Prices move because of taxes, or because a government makes electricity cheap, or because one country has better roads which makes it cheaper to move food around. These things don't show up in the exchange rate, but they change the life of every person living there. We're even starting to struggle with how to count things that are free, like a map on your phone or a search engine, which make life a lot better but don't cost anything at the shop.

HostThat burger on the menu might look like a steal to a tourist, but the local price tells the real story of what it takes to get by in that city.