Three years ago, Victoria Fierce was lured to the San Francisco Bay Area in hopes of landing a job with a major tech firm. Her employer in Akron, Ohio, had closed its doors and she was ready for a new beginning.

“I ended up sleeping on a friend’s couch until I could find my own place,” Fierce said. “After weeks of looking, I finally found an apartment that I could afford. I was on BART (Bay Area Rapid Transit) to go view the place and I got the call that the unit was just rented. Within an hour, it was gone.”

”Our core argument is that for the past 25 years we weren’t building enough housing for organic population growth. Census bureau data is used to inform how we measure our jobs to housing balance.”

— Laura Clark, Executive Director, YIMBY Action

The housing shortage crisis in the Bay Area and in many metropolitan areas is dire. Fierce’s experience was such a reality check that it inspired her to launch East Bay for Everyone, a pro-housing non-profit in Oakland, California, that advocates for more development, transit, tenant rights and long-term planning in the East Bay.

There’s a name for this growing response to housing shortages and astronomical housing costs: Yes In My Backyard, or YIMBY. It’s a counter-movement of sorts, running in opposition to NIMBY, the Not in My Backyard stance that has slowed development in many communities.

The costly San Francisco Bay Area was one of the first urban areas to start a YIMBY movement and it has since expanded nationally and internationally (popular in costly London, for example). YIMBYs will frequently describe themselves as upwardly mobile and tech-savvy Millennials who want more housing built to satisfy high demand. Their comfort with technology has made data an integral part of their advocacy.

Census Bureau demographic, housing and socioeconomic data, as well as building permit and employment statistics, have become essential tools in housing movements, whether it’s YIMBY or NIMBY.

Recently, the quest for housing affordability has dominated the national conversation. According to the 2016 American Community Survey (ACS) 1-Year estimates, 38.2 percent of rental households in the San Francisco Metro Area were spending at least 35 percent of their income on basic housing costs and 27.8 percent of homeowners with a mortgage were in the same situation.

In the nearby San Jose Metro Area, 37.2 percent of renters and 26 percent of homeowners spent at least 35 percent of their income for housing needs. East Bay for Everyone is one of several YIMBY organizations that have popped up in the San Francisco Bay Area and other cities. They are showing up at county and city planning meetings demanding that policy makers find solutions to the region’s housing crisis. They are pushing for more flexible zoning and more affordable high-density development.

Residents of communities across the nation, especially renters, are cost burdened. As defined by HUD (U.S. Department of Housing and Urban Development), anyone who spends more than 30 percent of their income on housing is cost-burdened. According to the ACS, nationally, an estimated 40 percent of rental households and 21.3 percent of households with a mortgage meet this threshold.

The 2016 ACS 1-year estimates show Bay Area housing as among the most costly in the nation. The median value of a single-family home in the San Francisco Metro Area is $796,100 and $911,900 in the San Jose Metro Area, with median mortgages at $2,842 and $3,072. Median rents are $1,757 and $2,044, respectively.

The 2016 ACS Median Household Income in the San Francisco Metro Area is estimated at $96,667 and in the San Jose Metro Area, it’s $110,040. YIMBYs say salaries have not kept up with the pace of the region’s galloping housing costs.

Michael Tsai grew up in the San Francisco Bay Area in the 1990s and attended University of California Berkeley, graduating in environmental economics in 2010, right in the middle of the Great Recession. Tsai made it through the economic challenges of those years working a variety of tech jobs. He also became passionate about solving the region’s housing affordability problems.

Nearly a decade later, he is a member of South Bay YIMBY and serves on a citizen-appointed commission for the city of Milpitas, just northeast of San Jose and about 40 miles southeast of San Francisco. Tsai’s passion has led him to be at the vanguard of the region’s YIMBY movement. At 29, Tsai still experiences the frustrations of feeling priced out of one of the most expensive real estate markets in the nation: He lives in a group home rental with several roommates.

YIMBYs portray their struggle as one in opposition to more established homeowners who have the political support of Home Ownership Associations (HOAs). These groups lobby for the preservation of suburban ideals, dominated by single-family homes and large backyards.

The lines between the two housing movements, are starkly dug along generational divides, Tsai said.

“I feel like we’re getting more interest from a younger generation, especially Millennials because they’re the ones bearing the brunt of this housing crunch,” Tsai said “The whole idea that you move out and get your own place has fallen apart in the Bay area.”

It was different for baby boomers, he said.

Michael Tsai - Member of South Bay YIMBY

“College was way cheaper back then and housing was cheaper back then so they basically profited from it but unfortunately there’s this attitude that ‘I got mine and you can’t get yours’,” he said.

Established homeowners deserve to have a voice in discussions about proposed changes in their communities, said Amy Repke, Vice-President for Communications and Marketing at the Community Associations Institute, an organization that advocates on behalf of HOAs. Repke said homeowners are increasingly educated about issues, are forward-thinking, and conduct research to help promote their interests.

“Communities are constantly evolving to fit the need of what homeowners want today and that’s exciting,” Repke said. “Homeowners today are far more in tune with wanting to be in the know and they’re driving those changes with data, including Census Bureau data.”

While existing homeowner and civic associations use data to promote appealing neighborhood features, YIMBYs rely on data to demonstrate that housing supply has lagged demand.

Laura Clark, executive director of San Francisco-based YIMBY Action and others in the YIMBY movement are supporting a bill in the California legislature. It proposes a data-based formula to determine housing unit quotas based on the number of new jobs in a jurisdiction.

”Our core argument is that for the past 25 years we weren’t building enough housing for organic population growth,” Clark said. “Census bureau data is used to inform how we measure our jobs to housing balance.”

While YIMBYs are frequently associated with Millennials, the movement’s adherents have grown more diverse in recent years. It now includes Boomer parents who want their grown children to be able to afford to live near them, senior citizens, recent immigrants, longtime residents who fear losing their homes because of gentrification and service workers in the Bay Area who don’t want to endure extreme commutes.

The movement has come under criticism from environmental groups and others because YIMBYs’ primary goal is to get any infill-development housing built. Clark maintains the criticism is unfair given the complicated reality of land-use policy.

Building a broader coalition of voices has been crucial as the movement has evolved, Clark said. YIMBYs have become more vocal about supporting higher-density and transit-oriented development, as well as affordable housing for lower-income households.

“You have to talk about values,” said Clark. “Census Bureau data show that the way things are going, we need housing in general to be more affordable for everyone.”

Nesreen Khashan is a data dissemination specialist at the Census Bureau. Lia Bolden is a partnership specialist in the Los Angeles Regional Office.