Andy Larsen: Do young adults choose to stay in Salt Lake City when they start working? How about Provo?

I love a data upgrade.

Back in April, I used some simple census data to answer a key, but pretty broad question: How many Utahns are from Utah?

It turns out that the answer to that is about 61%. We also were able to see that the percentage of Utah transplants hadn’t changed much: Native Utahns made up 67% of the state’s residents 50 years ago. It’s hard to say all of those new Utahns are ruining the place when their share of our population has only changed by six percentage points.

But a newer study, released by the census and the Opportunity Insights crew at Harvard University, answers more specific questions. They looked at essentially every American young adult born between 1984 and 1992 to see where they lived when they were 26 years old. Then, they matched that data with the parents who claimed them as dependents on their tax forms to see which area they lived in when they were 16.

Note the difference between “residents” from my April article and “young adults” in this week’s examination; the Harvard study looks at a more specific slice of life. But that’s a very important part of life, too: that’s when kids leave the home, perhaps go to college, and then enter the workforce. The decisions those kids make may reveal something about those communities, about what opportunities were available and most appealing.

Let’s dig in.

Movement to and from each city

First, a note: The Harvard study uses something called “commuting zones” when talking about areas, a term that will be familiar to economists, but wasn’t familiar to me. The idea is that county lines aren’t always the best defining borders when talking about where people live and drive to work. So they came up with 709 official commuting zones in America to try to define a city’s market more accurately.

There are quirks, though. Ogden, for example, is in Salt Lake City’s commuting zone (we’ll call them CZs), as are Tooele and Park City. But Provo, just 6 miles further away from downtown SLC than Ogden, is in its own CZ — along with the rest of Utah, Juab, and Millard counties. I see what they’re going for, but these definitions are not my favorite.

Regardless, it’s still interesting to see how young adults have moved into and out of various Utah CZs. Here’s the top 10 migration locations into and out of four selected Utah areas: Salt Lake City, Provo, St. George, and Moab.

A few takeaways from the lists:

• We see more movement to and from the smaller CZs than the larger ones, like Salt Lake City and Provo.

• There seems to be a correlation between the size of CZs people grew up in and where they prefer to move to. Salt Lake City 16-year-olds tend to move to large cities, with the exception of Provo and Logan. Meanwhile, people are moving to Moab from smaller CZs like Cortez, Colo.; Gallup, Ariz.; and Farmington, New Mexico.

• There’s more interchange between Utah cities and Phoenix than there is with Denver. I’m not sure I would have expected that.

• A majority of the Provo CZ’s 26-year-olds lived somewhere else when they were 16 years old.

• A majority of 16-year-old Moabites moved elsewhere.

Census data includes all children in the Census Numerical Identification Database — everyone with a Social Security number — which means we have near-exact data for even the most uncommonly traveled CZ pairs. Why is it not quite exact? The study adds or subtracts one or two to the number reported in each CZ pair to protect people’s privacy, especially in small CZs. Still, it’s fun to go through pairs of CZs to see how many people moved to and from each city: you can download the full data here.

Utah vs. the nation

So how do these numbers compare with the rest of America? Well, nationally, about two-thirds of 26-year-olds live in the same place they did when they were 16 — so the Salt Lake City CZ sees more people staying close to home than the national average, while the other Utah CZs see more mobility.

That’s validated by another way of looking at the data: the average distance 16-year-olds end up moving from home. The national average sees 16-year-olds move 181 miles, but Salt Lake City CZ teens move 165 miles from home, on average; Provo CZ teens move 175 miles, St. George CZ teens move 216 miles, and Moab CZ teens move 248 miles.

But this isn’t a flat curve: Note that 90% of 26-year-olds end up less than 500 miles from home.

You might wonder — well, how about older adults? There’s a little bit more movement about ten years later, but even the 35-year-olds in the sample haven’t moved drastically farther:

Fifty-eight percent of 26-year-olds have moved less than 10 miles, a number that decreases to just 48% by the time they’re 35. But only 3% more — 13% compared to 10% — move more than 500 miles away in those nine years.

A key difference: Black migration

But here’s one huge difference between Utah and the rest of the nation: migration for minorities. Nationwide, Black and Hispanic 16-year-olds are less likely to leave their CZ than their white and Asian counterparts.

In Utah, that trend continues for Hispanic folks, but is actually the opposite for Black people. In other words, Black 16-year-olds are more likely to leave Utah than white 16-year-olds.

Take the Salt Lake City CZ. Seventy-five percent of its white 16-year-olds stick around. That drops to 69% for Black teens. In Provo’s CZ, white 16-year olds stay at 67% — but Black folks only stick around at 58%.

Why is that? There are at least two plausible explanations. One is that, whereas Black teens in other parts of the country have less economic mobility on average, here in Utah, they have more. They might be more likely to be able to go to college, or have the means necessary to move. But it turns out that the Black/white discrepancy is true across the income spectrum: Black teens with parents with high incomes and low incomes alike are more likely to move out of their Utah CZs than high income/low income white teens. So I’m not sure I buy that explanation.

Another comes from the Harvard/census group themselves: “We find that Hispanic, Black and Asian individuals are less likely to leave the place they grew up in if that CZ has a higher fraction of same race/ethnicity inhabitants.” Then the opposite treatment would also be true: they’re more likely to leave the place they grew up in if they have a lower fraction of same race/ethnicity inhabitants. Utah’s Black population is quite low.

This could be a useful number to track, especially for those interested in increasing Utah’s diversity: If a larger proportion of Black Utah teens decided to stay here, it could influence the next generation to stay as well.

There’s a lot of powerful data here, and if you’re interested, I’d encourage you to check out the census/Harvard interactive map at migrationpatterns.org. There, you can check out more specific information for other races and ethnicities, along with data broken down by parental income.

But overall, I think it’s fair to say that teens in the Salt Lake City CZ are “stickier” than the national average, while those in more rural areas are more likely to move than the national average.

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