Between 2000 and 2014, the population of the District of Columbia grew by more than 15 percent to 658,893. That influx of people has raised, and continues to raise, concerns of various kinds inside the city. But one thing nobody says is that the newcomers are "taking jobs" from longtime residents. That's because it's pretty obvious that the influx of new people is in fact increasing the number of jobs in the city. All those new residents want places to eat, places to buy toilet paper, places to get their hair cut, places to work out, and all the rest.

Compared with how things were when I first moved to town over a decade ago, the city has more big-box stores, more supermarkets, more small shops, more bars and restaurants, more yoga studios, more nail salons, and generally more of just about everything than it used to. Because human beings aren't just competition for jobs — they're customers.

That logic is pretty obvious when we talk about movement within the United States of America, but as Gihoon Hong from Indiana University and John McLaren of the University of Virginia find in a new working paper, it also applies to international migration.

Using US Census data from 1980 to 2000, they found:

Each immigrant creates 1.2 new jobs for local workers.

A majority of the new jobs created go to native-born workers.

62 percent of the new jobs are in non-traded services — anything from dentistry to bartending to plumbing that can't be shipped across the country.

Immigrants raise wages in the local non-traded sector.

Immigrants attract native-born domestic migrants from elsewhere in the country.

Immigration is a contentious issue for reasons that, I think, don't have much to do with economics. But that tends to lead people to an excessively bleak view of the economics. It is possible that the world has changed in some profound way since 2000 that makes these results no longer hold, but I doubt it.

If you just forget about the world "immigration" and think about "a place that lots of people are moving to," I think it's obvious that for most people with most sets of skills "a place that lots of people are moving to" is a place with more job opportunities (you could teach their kids or clean their houses or cure them when they're sick or fix their electricity) than "a place that nobody wants to move to."

It's true that if the typical person were a farm laborer or worked in a mine, that it might make sense to worry about a fixed pool of resources being spread across a larger pool of workers. But the vast majority of people living in America are directly or indirectly selling services to other people living in America.

More people means more opportunity.