Like workers in most professions, teachers tend to fall along a bell curve. About 10 percent are outstanding, another 10 percent are struggling and the majority are somewhere in the middle doing satisfactory-to-good work.

Those floundering on the low end were the subject of a May 9 Star Tribune news investigation. Reporters Emily Johns and Norman Draper found that although Minnesota's education community knows there are ineffective teachers in the ranks, few are fired for incompetence.

Clearly, allowing bad teachers to continue in classrooms is a disservice to students, families, good teachers and the education system overall. It's bad for the poor performers as well. They deserve an honest assessment of their work and, if they don't improve, a push to find a career that's a better fit.

There are a number of fundamental steps the state and schools should take to address the problem. Administrators must be more serious about the three-year teacher probationary periods for new teachers, carefully evaluating new instructors before they receive tenure. For more experienced educators, Minnesota should develop a comprehensive evaluation system. With a uniform, statewide assessment tool, teachers and administrators would have a better sense of what is expected on the job and of how educators measure up based on a common set of standards. Finally, the state must do a better job collecting data on how districts are dealing with poor performers.

For too long, Minnesota has been behind the curve on teacher quality assessment. Several national studies have criticized the state for failing to fire ineffective teachers and having a weak system to evaluate them. A National Council on Teacher Quality report gave Minnesota an "F" in "exiting ineffective teachers." And the state recently lost out on federal Race to the Top education funding, in part because teacher quality policies were below par.

The state Department of Education doesn't track of how many low-performing teachers are fired. The best information comes from arbitration records. They show that since 1992, only 10 Minnesota teachers fired for poor performance have challenged their dismissals through that process. That's 10 cases among more than 60,000 state teachers.

As the Star Tribune report described, firing teachers is rare because the process can take months or years, cost districts tens of thousands of dollars and require hours of staff time to collect the evidence required to make a firing stick. Because dismissal can be so costly, too many administrators look the other way or find a way to manage around the problem. Some have tried to let an employee go, only to have firings overturned by arbitrators because of inadequate documentation

Union and school officials point out that they sometimes work together to quietly counsel teachers to leave, either voluntarily or with a settlement. That's typically a less costly way of handling the problem and allows both sides to save face, but there is no required tracking of those types of resolutions. There should be.

Principals and superintendents -- as supervisors who do the hiring, firing and job reviews -- must also be evaluated more effectively. Many Minnesota districts have taken a haphazard approach to overall performance assessment, but that will have to change if the state expects to compete nationally. Education Department officials say one of the conditions for accepting federal education stimulus funding is tracking teacher effectiveness.

Tom Dooher, president of the state teachers union, deserves credit for saying, "There is not room in teaching for ineffective teachers. The stakes are too high." The academic success of Minnesota students is indeed a high-stakes matter. And as long as Minnesota fails to take an honest, effective approach to dealing with poor performers in its schools, those students will be the real losers.