Jordan and Julia are in foster care, but they won’t be for much longer. Both are 17 and when they turn 18, they’ll “age out” of the foster care system. What happens next is a question the many King County agencies and organizations that serve homeless youth would love to have answered.

With limited staff and funds it’s a struggle to look after every 17-year-old nearing graduation from the foster care system. But what if they didn’t all need looking after? What if there were a reliable way to predict which foster kids are most at risk after exiting the system?

The United Way of King County set out to do just that. On Thursday, it released its Youth at Risk of Homelessness (YARH) report, which calculates that foster-care-to-the-streets risk. Based on the report’s methodology, the composite foster youth Jordan and Julia have vastly different chances of winding up homeless after they leave their foster homes: 62 percent for Jordan vs. 1 percent for Julia.

The YARH’s two-part report was funded by the Administration for Children and Families (ACF), which resides within the U.S. Department of Health and Human Services (DHHS). Part one of the report collects and analyzes data on youth leaving foster care. Part two uses that data to develop a plan of action. “We realized we were doing this planning around young people who were homeless,” says Courtney Noble of United Way of King County. “But we weren’t doing any upstream investigation.”

In other words, there was too much focus on the symptom and not enough on the cause.

Based on 2013 data from DSHS, the report identifies 1,213 young people, 17 or older, who left the state foster care system and did not return. About 25 percent, or 335, found themselves without a home at some point in the 12 months following their exit.

For the report, United Way enlisted DSHS to analyze available data on foster care alumni. including personal stories, in an effort to tease out who is more likely to end up homeless and why. Data came from the state’s child welfare, public school and health care systems as well as homeless service and housing assistance agencies. Data points included the number of foster care placements and any reports of abuse; high school GPAs and the number of school changes; use of emergency shelters and transitional housing; and the number of injuries or reports of mental health issues and substance use.

The report’s authors found that unstable housing, multiple foster care placements or changing schools a lot put young people at greater risk of homelessness. The report also concluded that “those [young people] who had experienced a disrupted adoption were three times as likely [to become homeless] and those who had parented a child were over twice as likely.”

Odds of experiencing homeless after aging out of foster care. African American youth, for example, are nearly twice as likely to become homeless after exiting the system. Source: Youth At Risk of Homeless report.

For youth with “protective factors,” such as one foster care placement with a relative and a high grade point average, the odds of experiencing homelessness decreased dramatically.

The fictional Jordan and Julia have a higher chance of becoming homeless (3.9 percent) in their first year out of foster care, due solely to the fact that they were in the system. That’s the baseline risk. When the report’s authors start plugging in other the aforementioned risk factors, Jordan and Julia’s risk goes up.

For example, if Jordan was homeless in the 12 months before he left foster care, his score rose 13.2 percent. Multiple (four or more) foster care placements, school changes, convictions (in the two years prior to exiting foster care), time in juvenile rehab and a history of behavior problems each adds 5-10 percent to Jordan’s score. In the final tally, his 3.9 percent risk of homelessness ballooned to 62 percent.