This year is already shaping up to be a tough one for teacher layoffs. But while that's bad news for teachers, it doesn't have to be bad news for their students, as this recent Brookings policy brief on class size by Russ Whitehurst and Matt Chingos points out.

Over the past twenty years, the nation's student-teacher ratio has declined 21%, to 15.3 students per teacher (student academic performance, we might add, has largely stagnated). Whitehurst and Chingos note that raising average class size by just one student would net the country $12 billion a year, or about the same amount the federal government spends on Title I.

Districts will have no choice but to lay teachers off this year, and class sizes are going to rise. But if districts make layoffs based on teacher effectiveness (as we advocated last year), student learning will be largely unaffected. The research, reviewed extensively by Whitehurst and Chingos, is clear: modest class size increases have virtually no impact.

So instead of bowing to the inevitable political pressure to sacrifice everything on the altar of smaller classes, district leaders would do well to redouble their efforts to improve teacher evaluation and bring an end to personnel policies that privilege teacher seniority over student learning.