Sandra Plantz, an administrator at Gallia County Local Schools for more than 20 years, oversees areas as diverse as Title I reading remediation and federal grants for all seven of the district’s schools. In recent years, though, she has leaned in hard on a role that is overlooked in many districts: homeless liaison. Ms. Plantz’s district, in rural Ohio, serves an area that doesn’t offer much in the way of a safety net beyond the local churches. The county has no family homeless shelters, and those with no place to go sometimes end up sleeping in the parking lot of the Walmart or at the hospital emergency room. Homeless students have the worst educational outcomes of any group, the lowest attendance, the lowest scores on standardized tests, the lowest graduation rates. They all face the same cruel paradox: Students who do not have a stable place to live are unable to attend school regularly, and failing to graduate from high school is the single greatest risk factor for future hom...