The head of a National Research Council committee says schools that are looking to hire teachers should keep an eye out for those with national board certification.

A report from the council says students taught by educators certified by the National Board for Professional Teaching Standards make bigger gains on standardized tests than other students do.

But the report notes it's uncertain whether the process of getting certified by the national board makes teachers better or if those who get certified were already top performers.

Milton Hakel of Bowling Green State University, who headed the committee that prepared the report, says more research is needed to determine that.

Still, he says there's a clear signal in the report that superintendents hiring teachers should look for the national certification.