Emily Fox speaks with Brookings researcher Elizabeth Kneebone, co-author with Alan Berube of "Confronting Suburban Poverty in America."

Kneebone and Berube chose five locations to study for their book. South King County was one of them, Kneebone told Fox, because it demonstrates so many national trends.

Kneebone: "There's a large refugee resettlement population there, there's a large immigrant population there, so growing diversity in terms of people moving into the community.

"But at the same time that's not the only driver. You also have these structural economic changes, like the growth of low-wage work and the impact of two recessions, that have also led to downward mobility among long-term residents.

"So just as all these drivers are coming together in particular ways in South King County, it helps us tell the story of what's happening nationally in so many places that are grappling with similar trends."