Originally published on The New York Times.

Some children lost a stable home when a parent succumbed to opioid addiction. Others were forced to stay in hotels after hurricanes or fires destroyed their homes. Still others fled abuse or neglect.

More than 1.5 million public school students nationwide said they were homeless at some point during the 2017-18 school year, the most recent data available, according to a report from the National Center for Homeless Education released last week.

It was the highest number recorded in more than a dozen years, and experts said it reflected a growing problem that could negatively affect children’s academic performance and health.

“The ripple effect here is real,” said Dr. Megan Sandel, a director of the Grow Clinic at the Boston Medical Center, who said housing instability was associated with developmental delays in children and children in fair or poor health.