My friend, Jason, is a superb French horn player; I am mediocre at best (my motto: "I'm not good but I make up for that by being loud.").
At the same time, we are both also conductors. I'm a pretty decent conductor but Jason is probably better because of his talent, background, experience, and musical knowledge.
So, in economics jargon, Jason has an absolute advantage over me in both playing French horn and conducting. But if he tried to do both at the same time, he would probably not be so good (though I expect he'd be more than passable).
Overall, Jason is tonnes better than me at playing French horn and only somewhat better than me at conducting. So, again in economics jargon, Jason has a comparative advantage over me in playing, which leaves me with a comparative advantage in conducting.
The neato Ricardian theory of comparative advantage suggests, therefore, that I should be conducting and Jason should be playing French horn in our community band.
It doesn't work that way, though. Why not?
First, there are four people in the band with conducting experience, not just Jason and me.
Second, there is only one paid position in the band: conductor. Given the choices, Jason chooses to take the paid position rather than play French horn (an unpaid position). And given the options, the band chooses to hire Jason to do the conducting instead of me because he is the better conductor.
So even though the theory of comparative advantage suggests the band would be better off with Jason on horn and me conducting, it doesn't always work that way when prices and wages are not completely flexible and determined in competitive markets.
Notes:
- the above thoughts occurred to me during a rehearsal in which I butchered a few horn solos and I wished Jason had been playing them instead of me.
- it might even be more efficient to have both Jason and me play French horn and have someone else conduct the band. But I expect Jason has a comparative advantage in conducting over them; besides, I think he quite likes the job. In the past, we did indeed have a different conductor, and Jason and I both played French horn, but that conductor has retired from the position.