New research confirms the link between chronic absenteeism — defined as a student not showing up on 18 or more days — and a school’s average test scores. For every percentage point increase in a school’s chronic absenteeism rate, the number of students passing the New York State ELA and math tests goes down by 1.3 percent, finds a new report from the Center for New York City Affairs at the New School’s Milano School of International Affairs, Management and Urban Policy.

Chronic absenteeism has been gradually declining over the past five years, although it is still prevalent in many city schools. The report, which is the latest in a series on the topic, finds that 19 percent of children in elementary or K–8 public schools miss 18 or more days, down from approximately 23 percent in 2008. At 130 elementary and K–8 schools, at least one-third of students are chronically absent. Not surprisingly, these schools have the greatest challenges — and the lowest scores.

To better understand the roots of chronic absenteeism, researchers Kim Nauer and six colleagues used U.S. Census data to examine the neighborhood of each of the 130 schools according to 18 poverty indicators. They found a close connection between the number of poverty indicators present in a school’s neighborhood and the number of chronically absent students at the school. The level of chronic absenteeism was lower in schools in low-income neighborhoods with fewer than 10 poverty indicators where households are relatively stable than it was in schools in areas with 10 or more poverty indicators that serve students living in deep poverty and often unstable households.

Researchers identified three successful approaches to tackling chronic absenteeism: rewards for good attendance, family intervention from a guidance counselor and, for the most persistent problems, family intervention from a social service agency.

The researchers suggest that principals closely track chronic absenteeism even when a school’s average daily attendance is above 90 percent. They note that average daily attendance measures only the percentage of students who show up for school on a given day and doesn’t capture how many students are missing too much school.