Saying we should “reward excellence and incentivize success,” Oklahoma House Speaker Lance Cargill is leading an effort to establish merit pay for schoolteachers. “In each of the last four years,” he says, “Oklahoma has raised teacher pay at a pace virtually unsurpassed in the country. In the future, however, raises should be tied to performance.”

Cargill’s idea makes sense. According to the federal Bureau of Labor Statistics (BLS), in 2005 the average public school teacher’s salary in Oklahoma City was $34,896. But let’s not forget that, on average, teachers work fewer hours a year than other professionals.

According to these official government numbers, in 2005 the mean hourly earnings for a public school teacher in Oklahoma City was $26.08, which was about two percent higher than the average hourly earnings of those in comparable professions in the state. What’s more, these figures do not include benefits such as health care and pensions, which are usually more generous for public school teachers than for other professionals.

The BLS found that public school teachers’ hourly earnings are about the same as those for other professionals like architects, economists, biologists, civil engineers, chemists, physicists, and astronomers. Even those in demanding, education-intensive professions like electrical and electronic engineering, dentistry, and nuclear engineering didn’t make much more than teachers per hour worked.

Some argue that it’s unfair to calculate teacher pay on an hourly basis because teachers perform a large amount of work at home—grading papers on the weekend, for instance. But people in other professions also do offsite work. The only important question is whether teachers do significantly more offsite work than others.

Unfortunately —and this points up precisely why merit pay is such a good idea—teachers cannot be rewarded for extra work they take home because their salary is largely determined by years of service and advanced degrees obtained, not the quantity or quality of their effort. Thus, contractual hours provide a meaningful basis for discussing teachers’ earnings.

It is important to keep in mind that the above figures are for the average public school teacher, not each teacher. But again, focusing on the average teacher is appropriate since we pay public school teachers in a uniform way that is unrelated to performance. The current system does not allow us to reward those teachers who are working the hardest and who are making the biggest difference in the lives of their students.

Some recent evidence suggests that altering the current system to compensate teachers in part based on the academic performance of their students leads to greater student learning. With colleagues at the University of Arkansas, we found that paying teachers for their classroom performance substantially increased math proficiency in Little Rock. David Figlio and Lawrence Kenny also evaluated performance pay using nationwide data and found that it led to large academic improvements.

Until we stop hiring and financially rewarding teachers according to qualifications that are irrelevant to their performance, it will be hard to expect improved quality in classroom instruction.

Jay P. Greene (Ph.D., Harvard University) is the endowed chair in education reform at the University of Arkansas and a senior fellow at the Manhattan Institute. Marcus A. Winters (Ph.D. candidate, University of Arkansas) is a senior research associate at the Manhattan Institute.