Production Possibilities Curve as a model of a country's economy | AP Macroeconomics | Khan Academy

Let’s say that we have some country, let’s call it Utense Landia, that can only produce one of two goods or some combination of them. So it can produce forks, and it can produce, or it could produce, spoons. This axis is the quantity of forks; this axis is the quantity of spoons.

Let’s say that if it put all of its energy into forks, well, it would produce that many forks and no spoons. But then, if it tried to focus some of its energy, some of its resources, on spoons, well then it would produce fewer forks. The more spoons it produces, the fewer and fewer forks it will produce, all the way to the point that if it only focused on spoons, well, it could produce that many but then it would produce no forks.

What this curve is—and we touch on it in other videos—this is the production possibilities curve for our country of Utense Landia that makes utensils. Obviously, most countries are much more complex; they don’t only produce some combination of two things, but this helps us. This is a nice model for understanding what countries might be capable of.

Now, one way to understand this production possibilities curve is it shows what can be efficiently produced by this country. If it efficiently utilized all of its resources, then it will produce some combination of forks and spoons that sit on the production possibilities curve. So this point right over here, this combination of spoons, which would be that many spoons and that many forks, this combination over here, this would be efficient. That point X would be an efficient production for Utense Landia.

At this point right over here, let’s call that point Y. Now, what happens if Utense Landia goes into some type of a recession? For whatever reason, it’s not able to use its resources as efficiently. We’re talking about resources; we’re talking about land, we’re talking about maybe its factories, we’re talking about the materials it has, maybe it’s labor.

Well, in that situation, let’s say it was operating efficiently here, but then the recession happens, and so then it operates right over here. Let’s call this point right over here Z. This would be an inefficient use of its resources, sitting behind the production possibilities curve. So this is inefficient, just like that.

One question you might have is, well, what about points that are beyond the production possibilities curve, like point—let’s just call that point A right over there. What about that point? Well, unless you have more inputs, unless you have more land, more capital, more labor, if you don’t change the resources here, this is actually going to be an unattainable point for Utense Landia.

But let’s say you really want to reach it. How can that happen? Well, you can actually have investment, or you could have more land or more labor. So let’s think about that scenario. Let me draw the two axes. So that’s my fork axis; that’s the quantity of forks that Utense Landia will produce in the year. This will be the spoon axis right over there.

Let’s draw our original production possibilities curve. I’ll try to make it look pretty similar to what we had before. So that’s our original production possibilities curve. Another way of thinking about it is it’s showing the trade-off between producing forks and spoons. You can actually think about what is the opportunity cost of producing an incremental spoon in terms of forks—how many forks do you have to trade off?

Because remember, there’s scarcity at play; you don’t have an infinite amount of metal to produce things with, an infinite amount of labor, or an infinite amount of factories. But let’s say Utense Landia, they are able to get some more land on which to build factories. Maybe they build some more factories, so capital goes up. Maybe some people migrate to Utense Landia. So in that situation, you would have growth.

So this would be, and your production possibilities curve would actually shift outward. So here we are showing—let me make it a little bit—we are showing a situation right over here. This is still a production possibilities curve, but we’re showing what happens when you have growth.

And once again, what are the drivers of growth? Well, this could be your—the amount of land that you have goes up; the amount of capital that you have goes up. Capital could be things like factories; it could be machinery. You could have people—more people are able to help produce the spoons or forks. You could just have better technology for producing spoons and forks.

Sometimes people will even talk about entrepreneurial spirit, that people are able to figure out better ways of combining these resources so that you could produce more spoons or forks. But let’s imagine now the other scenario. Let’s imagine a scenario where Utense Landia gets into a war with Platelandia, and Platelandia sends their bombers in and starts destroying some of the factories of Utense Landia.

So what will happen in that situation? Before the war, this is that production possibilities curve for Utense Landia, but now because of the war, maybe Platelandia is able to take some land from Utense Landia. Maybe it’s able to destroy some of the factories and other forms of capital.

Maybe people flee Utense Landia, so there is less labor. And maybe, for whatever reason, they can support less technology, or they forget how to use some of their technology because the war is so long and protracted. Well, in that situation, your PPC—you would see contraction and contraction. I could depict it.

Let me shift my PPC, my production possibilities curve, inward just like this. So this is a situation where we are seeing contraction. So big picture here: your production possibilities curve is exactly what it says it is; it shows what can—a what is the potential combination of, in this case, goods that this nation can produce.

And if you’re sitting on the curve, it shows that that nation, that country, is efficiently using its resources. If you’re sitting within the curve, it’s inefficiently using those resources. And if you’re on the right of the curve or beyond the curve, well, that’s a situation where, if you don’t change the inputs, all else equal, this would actually be unattainable.

The way that you actually do attain/get to points beyond the curve is by shifting the curve itself, by having more land, more capital, more labor, or more technology, which we see in this middle scenario.