Winter storms don't carry the economic wallop of, say, a major hurricane or tornado. Icy roads don't create enough fender-benders to top wind and water damage to homes and commercial property.
But snow does close schools — and evidence is mounting that for every snow-day closure, students do worse on standardized tests. In an average Maryland winter, where schools close four to five days because of bad weather, the share of students scoring "proficient" on standardized math tests falls in comparison with years with no winter closures, according to a 2007 study.
The 1 to 2 percentage point drop isnt' huge, but it's significant, says Dave Marcotte, a public policy professor at the University of Maryland Baltimore County, coauthor of the study. "That's on the order of changing the class size by three to four students in the class."
The effects can be especially hazardous for marginal schools. Since testing typically takes place in winter, the loss of four or five instructional days can be the difference between achieving the mandated "adequate yearly progress" or failing. In the 2002/2003 school year, for example, 35 of the 56 Maryland elementary schools that failed would have passed had they been open all scheduled days, estimates Professor Marcotte. "Interrrupting a full week or two of class is real dangerous for these schools."
Other researchers have found similar results in other states.
Winter closures may only be a temporary setback for schoolchildren, because school districts generally schedule extra make-up days at the end of the year for snow days, Marcotte says. Then again, children may lose out permanently because of snow days. "There's some concern that at the end of the year ... kids have a different ability to focus on school when the pool is calling," he says.
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