The Associated Press reports that in a speech to the National Urban League, New York City Mayor (and possible independent presidential candidate) Michael Bloomberg promoted merit pay for teachers: “Bloomberg said some critics believe that offering financial incentives to teachers somehow diminishes their altruistic motives – an idea he denounced as ‘ridiculous.'”

If “financial incentives” really diminish teachers’ “altruistic motives”, why do so many teachers unions take their members out on strike for more money? Wouldn’t an across-the-board pay raise be an across-the-board drop in altruism?

Merit pay, of course, is largely anathema to America’s largest teachers union, the National Education Association: “NEA members, a key Democratic constituency, have expressed concerns about merit pay, saying they worry that linking their pay to their students’ test scores would be unfair to those instructing kids from disadvantaged backgrounds.”

A valid concern … as long as merit pay evaluations don’t measure where kids start out.