With a snowstorm bearing down on Massachusetts, many of the state's school districts, including Boston, made the decision on Tuesday to cancel classes Wednesday.
But a Harvard study provides some backing to the call to cancel classes — at least when it comes to student achievement.
Its central finding: School closures don't impact student achievement, but absences — like when some students can't get to school in bad weather — are detrimental to learning.
"[S]chools are prepared to deal with coordinated disruptions like snow days," Joshua Goodman, a Harvard Kennedy School assistant professor, writes in his study (PDF). "Schools do not, however, seem to deal well with less extreme disruptions in which only some students are absent."
He adds: "With slack time in the schedule, the time lost to closure can be regained [often through makeup days]. Student absences, however, force teachers to expend time getting students on the same page as their classmates."
To the Harvard Gazette, Goodman said administrators "need to consider the downside when deciding not to declare a snow day during a storm — the fact that many kids will miss school regardless, either because of transportation issues or parental discretion."
Goodman conducted the study in 2012 at the request of the state Department of Education, which wanted to know the "achievement costs of snow days." The study was never published widely, according to a Harvard spokesman, and the university wrote about it Tuesday.