It's time for schools to reward good teachers the way private companies reward good workers: by letting their senior managers -- the school principals -- decide who's doing the best job and divvy out the cash.

This year, Utah schools and teachers are experimenting with merit pay. Each school district and charter school will develop its own plan for allocating the $20 million the Legislature has authorized statewide.

Merit pay is plainly a good idea for schools. For too long, actual performance in the classroom has been a non-factor in teachers' salary scales. The result is that subpar or ordinary teachers hang on until retirement, while more ambitious and talented educators move on to fields that recognize and reward superior effort.

The fruit of the process has been mediocrity in the academic performance of American students compared to students in many other developed nations.

Merit pay is the system every private enterprise uses attract talented, energetic people and keep them on the job. It is the most practical way for rewarding skilled professionals.

But how? A recent Daily Herald story noted that school districts and charter schools are adopting a variety of schemes. A look at some of the ideas being floated around Utah Valley raises some questions.

Local schools will not base merit pay solely on test scores. That's reasonable. Tests have their place. But they have limitations, too. A good teacher could wind up with kids who are already behind in school, and a poor teacher could wind up with kids who'd do well on tests anyway.

In Alpine School District, teachers will do a self-assessment and be evaluated by a team of parents and administrators. Most people would like to assess their own work performance, especially if raises are at stake. Parental involvement is good, but it's not clear that teachers who have curried favor with parents are necessarily the best taskmasters for the children.

Alpine teachers will also get points for their work in collaborating with other teachers. Collaboration is one of those vague buzzwords that sound nice, but "working together" doesn't seem like a results-oriented performance standard focused on students.

Provo has outlined eight "pathways" to the bonus. Somehow this sounds like way too many alternative routes -- and of varying value. For instance, one pathway would be gaining more education. Again, that's not a results-oriented standard.

There are plenty of people with a list of degrees and seminars as long as your arm who can't teach their way out of a paper bag.

At the same time there are teachers with minimal credentials who can move students to new heights through their ability to connect. Teaching is an art form that is not automatically enhanced by paper certificates or other trappings of the education establishment.

The focus should be on what a teacher actually does for students -- which seems to suggest that some measurement of students should be used as a gauge to the value of a teacher.

So here's a puzzler: Nebo School District places more emphasis on test scores than its neighbors. But it allows some wiggle room to give bonuses to teachers whose students fail to improve on tests. Go figure. Either the tests are a valid measure or they're not.

It's true that administrators and board members who are trying to put together a pay system deserve some sympathy. Except for sales people working on commission, it's hard to decide what professionals are worth. Many factors can't be easily measured.

But this doesn't mean that subjective measures are invalid. Most private companies realize that, and they give their managers the responsibility of deciding who gets paid what. The managers see the work first-hand and are qualified to judge it.

Principals are the front-line in the public schools. They see how the teachers work, how the students respond, what the parents think. They can factor in whatever measures seem useful, including test scores. They're also in the best spot to gauge the intangibles.

All of which is why they should be in charge of setting salaries. They're responsible for what happens at school, so they should have all the powers they need to get the best results. The power of the paycheck definitely should be among them.

At this point an objection invariably arises: Principals would favor their friends. Principal's pet would become the new objective. The fawning factor would increase.

Such baseless worries should not be allowed to become a pretext for installing a purely objective reward system in a largely subjective line of work. The answer to fears of principal abuse is obvious: put the principals on merit pay, too. Then their own pay will depend on how well their staffs do, regardless of personal relationships.

It is true, in theory, that a renegade principal here and there could discriminate unfairly against an individual teacher. But a personal profit motive should suppress such tendencies.

We see an analogy in the framing of the U.S. Constitution. As James Madison pointed out in Federalist 10, the Constitution was not perfect as proposed in 1787, but it would dampen instability and the effects of the bad judgment of the few.

So would a rule tying principals to overall school performance.

All in all, the subjective judgment of a school principal provides the fairest and most effective means to administer merit pay.

Lose the bureaucracy; lose the lists of seminars; lose the certificates; lose the political swamp of parental input. Let the principals alone make use of all their presumed skill in recognizing classroom excellence to evaluate teachers fairly.

Principals should be left alone to weigh all appropriate factors, including the rate of academic improvement of students within a given class, as opposed to a static test score. Principals should be unfettered, not chained to a particular metric.

Principals should be given an absolutely free hand to reward and promote success. If, as some opponents to merit pay claim, teaching is too subjective to evaluate by objective measures (a reason given for labor union pay schedules), then let their subjective work instead be evaluated by a subjective judge -- a judge who is in a position to know what's going on.