With his endorsement of the "merit pay" concept applied to the nation's teachers, President Obama has tossed out what ought to kick-start conversations, not kill them.

This week Obama raised eyebrows among members of teachers' unions, which have been generally resistant to the idea, when he delivered a wide-ranging education speech in Washington, D.C.

"Good teachers will be rewarded with more money for improved student achievement, and asked to accept more responsibilities for lifting up their schools," he said.

That should be encouraging to teachers, who in a faltering economy can't begin to see many other prospects for improving their pay rates.

Up to this point, the National Education Association and its local affiliate, the Hawaii State Teachers Association, have been unconvinced. The objections are based on concerns that merit pay will be awarded on an inequitable basis, heightening divisiveness among competing teachers.

The biggest concern, and it's a valid one, is that teachers will be rewarded using only traditional student achievement gauges: test scores. Whether the criterion is high marks or trends that show improvement over time, teachers' merit pay would depend, unfairly, on where they teach.

Clearly, for merit pay to improve teaching and success in the nation's classrooms, it would need to be based on multiple achievements, most of which lie largely within the teacher's control. Studies have shown student progress correlating with increased teacher quality, something that means more than advanced collegiate degrees.

It means efforts to enhance teaching methods, professional enrichment programs and additional duties that teachers take on for the benefit of the kids. Many teachers do these things now, without thanks and without a salary bump.

That should change, in Hawai'i and nationally. The current contract negotiations between the state and HSTA would be an opportune time to begin the search for a merit-pay formula to add an incentive for teaching excellence, one that could reward students with a brighter academic future, as well.