PRINCETON - (AP) - New Jersey's acting education commissioner is calling for major changes in the way teachers are evaluated and paid.

He wants to make it tougher for teachers to get tenure protections and easier to lose them.

Christopher Cerf offered his proposals in a speech at Princeton University yesterday.

He says it doesn't make sense to pay teachers based only on the degrees they hold and how long they've been on the job.

Cerf said a primary factor should be how well their students learn. And he said those who teach in challenging schools or hard-to-fill subject areas such as science and bilingual education should be paid more.

He also said teachers should get tenure protections only after three years of high marks on evaluations and could lose that status after one or two years of poor marks.