For a year now, local business leaders have been making the case that if the St. Louis region hopes to grow its economy, it needs to attract more immigrants.

Largely left out of the conversation so far, though, has been a key question: How?

The answers will begin to come Thursday, when the newly renamed St. Louis Mosaic Project kicks off its next phase. The project will present a second study, offering some ideas on how St. Louis might draw more newcomers, and start fleshing out a fuller plan. And they’ll start to raise money for the effort.

Project director Betsy Cohen didn’t want to disclose too many details ahead of Thursday’s summit, but she said the ideas would include ways to help connect international college students here with area job opportunities, and to add foreign-born focus to current training and small business programs.

“We don’t have to start from scratch,” she said.

Still, the stated goal — having the fastest immigration growth of any big city in the U.S. by 2020 — is a tall order, largely for the same reasons St. Louis drew relatively few foreign migrants in the last two decades. People who study why immigrants move where they do point to two main factors: Current communities and economic opportunity.

“Social networks have become really a huge part of who’s coming and where they’re going,” said Jeanne Batalova, a demographer at the Migration Policy Institute in Washington. “They’ve really become the oil in the immigration machine.”

Newcomers, Batalova said, are more likely to go where they already know people, be it family, friends or people from the same town. It’s a way to break in to a new life, to find a job and a place to live. But those well-worn paths often don’t lead to St. Louis.

Aside from Bosnians after that country’s war in the mid-1990s, St. Louis doesn’t have any particularly large immigrant communities. There are significant pockets of Mexicans, Vietnamese, Chinese and Indians, and more recent arrivals from eastern Africa and central Asia. But St. Louis largely missed the immigration boom that reshaped many cities over the last 20 years, and big numbers went elsewhere. Today, of the 25 biggest metro areas in the U.S., only Pittsburgh has a lower share of its population that was born abroad.

Some of those places that drew many newcomers — such as Atlanta, Denver and Seattle — were not big gateways when the last immigration wave started, Batalova said. But they had something else to offer.

“Jobs, jobs and jobs,” she said. “The main driving force for most people is economic opportunity.”

On that, St. Louis doesn’t stack up so great either. Job growth here has lagged behind the nation for most of the last decade, and the region is still struggling to build back 60,000 jobs it lost in the recession. Indeed, the whole point of this immigration push is to change that, to spark economic growth on the theory that immigrants who do move here tend to be well-educated and are more likely than average to start a business. That in turn employs people and helps other businesses grow.

“We’re trying to make the pie bigger for everyone,” Cohen said.

St. Louis is not the only place trying to flip its economic script through immigration. A number of cities across the Midwest and Northeast are wrestling with the same chicken-and-egg dilemma. And what they’re learning could help point the way for St. Louis.

CLEVELAND REACHING OUT

How do you tell somebody about your city if they’re not here? The Internet helps.

The web is a big piece of Global Cleveland’s strategy to put their city on migration map. The two-year-old agency is launching a social media campaign and online portal designed to help potential residents understand the city better.

“It’s really going to be a one-stop shop, everything I’d want to know about what life here is like,” said Joy Roller, Global Cleveland’s president.

Global Cleveland is targeting not just immigrants but also “boomerang” migrants who moved away, and others. Still, newcomers from abroad are a big piece of the pie. Global Cleveland has launched programs aimed at boosting the region’s Latino and Asian populations, in the hopes that they’ll draw more friends and family over time.

“Really it’s been building communication tools for people who are already here,” Roller said. “To send out to people who might want to come here.”

And they’re trying to tackle one of the trickiest things for anyone moving to a new town: finding a job. Last fall the organization sent a staffer to a job fair in Puerto Rico to recruit college students for companies in Cleveland. This spring they’ve gone virtual, hosting online job fairs for medical and IT employers. They advertised widely, Roller said, and got wide results. The IT job fair drew applicants from 25 countries.

DOOR TO DOOR IN DETROIT

Detroit has been at this a little longer, long enough to see what the challenges are.

The four-year-old Global Detroit program has made a big push to keep more of Michigan’s 23,000 international college students in the state after they graduate. Despite the state’s well-documented economic woes, said director Steve Tobocman, many of the graduates would like to.

“Getting them to stay in Michigan hasn’t been a tough sell,” he said. “Getting companies to look at the opportunities is a continuing challenge.”

Even with some industries facing a shortage of skilled workers, it can be hard to get corporate recruiters to focus on international students, Tobocman said. They’re bombarded not just with job applicants but with similar groups trying to help veterans, older workers, people with disabilities. Breaking through takes a lot of door-to-door relationship building.

“It’s shoe leather,” he said.

They’ve also learned that programs that help immigrants can help other people, too. Global Detroit runs a micro-finance program that trains and lends to small businesses in several city neighborhoods. It’s geared to serve immigrants but is open to all. Six months in, 85 of the program’s 100 graduates have been U.S.-born African-Americans.

“We’re not hitting our metrics with the immigrant community, but that’s OK,” he said. “This helps make the case that the strategy we’re pursuing is a universal one.”

PLUGGING IN TO PHILADELPHIA

Maybe no city has enjoyed a bigger immigrant-fueled rebound than Philadelphia. Like St. Louis, the City of Brotherly Love had endured decades of emptying out. But by 2010, thanks largely to foreign-born newcomers, that had changed. The city was growing again.

“We had 60 years of losing population,” said Amanda Bergson-Shilock, outreach director at the decade-old Welcoming Center for New Pennsylvanians. “If it hadn’t been for immigrants it would have been 65.”

Many of those immigrants didn’t initially set out for Philadelphia. Three-fourths of foreign-born residents in parts of Pennsylvania the Welcoming Center has studied first lived someplace else in the U.S. Cities that offer a higher quality of life for less money can hold appeal over crowded gateway cities.

“Immigrants are often pretty flexible,” she said. “When you’ve moved from Sudan to New York, moving from New York to Philadelphia is pretty minor.”

But, she said, it takes more than smiles and a festival to make newcomers stick in a new town. Helping them plug into opportunities is essential. That means help with jobs, housing, school for the children, higher education. And it helps to provide those services in the neighborhoods where immigrants — and everyone else — lives, not just some downtown office building.

Do that, Bergson-Shilock said, and people will find their way to any city.

“The immigrant grapevine is a pretty powerful thing,” she said. “If someone moves to Philadelphia and someone helps him build a life here, other people will hear about that.”