It’s a rite of spring in the education field. Districts traditionally send layoff notices to far more teachers than they actually intend to let go. This year, however, they mean it.

Not only are state and local budgets still under strain, but the last of the federal stimulus dollars meant to keep teachers working -- the so-called EduJobs funds -- are about to run out. As a result, two-thirds of all districts are planning to let people go, according to surveys by the American Association of School Administrators.

Individual districts, such as Detroit and New York City, are talking about having to drop upwards of 5,000 teachers apiece, so layoffs in excess of a quarter million educators nationwide are possible. “Usually lots end up getting hired back,” says Andrew Rotherham, an education consultant, “but this year there will be real layoffs, year-over-year reductions.”

This is leading not only to the prospect of larger class sizes, but also concerns that young people will shy away from entering what is suddenly a less-than-secure profession. The number of students earning credentials in California, for instance, has already dropped by more than 50 percent from its peak in 2003-2004, while enrollment in teacher preparation programs dropped by a third over the past five years.

There are still plenty of teachers -- hence the layoffs -- so the major policy debates turn on the question of who should be shed. Traditionally, seniority has been the decisive factor, but a handful of states have recently passed legislation calling on districts to base their picks on classroom performance, rather than just years on the job.

“None of us want to see school districts have to make layoffs due to budget constraints,” says state Rep. Alisha Morgan, sponsor of a Georgia bill ending seniority-based layoffs. “But in case they do, we want them to make decisions based on the best interests of the students.”

Morgan’s bill leaves a lot of discretion to districts in terms of determining how best to evaluate performance. But she was disturbed by testimony from school board officials that indicated they were nevertheless more comfortable making such decisions based primarily on seniority.

That’s all too often the case, says Rotherham. Even when districts are freed from traditional personnel rules, they still largely adhere to seniority, rather than making tough calls comparing individuals.

That means many schools, even as they shrink the size of their workforces, are going to miss an opportunity to ensure that they’re keeping their strongest possible lineups intact. “This can be a chance to hold onto really good people, and get rid of bad people,” Rotherham says. “What’s frustrating is that schools don’t [see] the silver lining.”