Education changes are underway in many places — possibly including New York City. Mayor Michael Bloomberg wants to use student test scores as one factor in teacher tenure decisions.

The fight with the teachers’ union is expected to be bitter. But Bloomberg makes an excellent point in the closing quote below, as reported by the New York Times:

The city already uses test scores in evaluating the system: to determine teacher and principal bonus pay, to assign the A through F letter grades that schools receive and to decide which schools are shut down for poor performance. The mayor is now putting even more weight behind those scores by using them to decide which teachers should stay and which should go.

The Bloomberg administration contends that it already has the power to use test scores in tenure decisions. But, he said that the Legislature should require all districts in the state to evaluate teachers and principals with “data-driven systems,” one of the factors Education Secretary Arne Duncan will use in deciding which states will receive Race to the Top grants.

The mayor also said the state should allow teacher layoffs based on performance rather than seniority, as they are now.

“The only thing worse than having to lay off teachers would be laying off great teachers instead of failing teachers,” Mr. Bloomberg said. “With a transparent new evaluation system, principals would have the ability to make layoffs based on merit — but only if the State Legislature gives us the authority to do it.”