Teacher evaluation is definitely an area to watch as the Senate debates a renewal of the No Child Left Behind Act.

Some Republicans might be open to giving a second look to the bill from U.S. Sen. Tom Harkin, D-Iowa, bill reauthorizing the Elementary and Secondary Education Act if improvements can be made in the area of teacher evaluation and achievement gap schools.

Under the Harkin bill, due to be marked up starting Oct. 18, states would have to craft new systems with teacher input, using multiple measures including student outcomes and classroom observations. By contrast, a bill introduced by Sens. Johnny Isakson, R-Ga., and Lamar Alexander, a Tennessee Republican, would not include a separate category for achievement gap schools. And it would leave the decision about whether to craft new evaluation systems up to states and districts. Some Republicans would like to see similar language in the Harkin bill.

In a politics-makes-strange-bedfellows twist, the National Education Association wrote a letter to Alexander praising his bill’s handling of evaluations. And the NEA has flagged the evaluation language in the Harkin bill as an area of concern.

Of course, Democratic reform groups, many of whom already have issues with the bill’s handling of student subgroups, have asked for something much stronger in the teacher evaluation area. Harkin, who is the chairman of the Senate education committee, clearly has to do a bit of a balancing act on this.