If one of three competing state House bills become law, financially strapped Pennsylvania school districts soon could furlough teachers based on poor performance rather than on the length of time they've been on the job.

That seems like common sense:

Why throw younger, more-effective teachers over the side while keeping the dead weight on board?

State Rep. Seth Grove, R-Dover Township, introduced one of the bills and is cosponsoring the other two.

The specifics vary, but each allows districts to use the state's new teacher evaluation system, rather than seniority, when making furlough lists.

The lawmakers say the bills give districts the flexibility they need to keep the best teachers in their classrooms.

If we could be sure that's actually how such a law would work, we'd have no problem with it.

However, we share a concern of Wythe Keever, a spokesman for the Pennsylvania State Education Association, a statewide teachers' union with more than 182,000 members.

He suggests more experienced teachers would be targeted for furloughs not because they're less effective, but because they cost districts more in salaries and benefits.

Could districts do that?

Would they?

If their financial situations are dire enough, it's easy to see how they might try.

Grove counters the state's new teacher evaluations will protect effective, tenured teachers just as they would younger, up-and-comers.

We agree that's how it should work, but we don't know for sure.

The new system for grading teachers only took effect this year, and the first full evaluations won't be complete for a year and a half.

The new measurements certainly are an improvement over the previous system, by which teachers were rated either satisfactory or unsatisfactory -- based solely on classroom observation -- and nearly 100 percent were deemed satisfactory.

Now, teachers will be judged on three additional components of differing weight that include 22 sets of data.

While classroom observation remains part of the evaluation and accounts for half of the new formula, the other half is based on student achievement: 15 percent for a "school performance profile," 15 percent for "individual teacher measure" and 20 percent for "elective data."

The school performance profile includes data such as PSSA test and SAT scores as well as graduation and attendance rates.

The individual teacher measurements consist of data the department began compiling this year, but they will not be included in the evaluation until the end of the 2015-16 school year, at which point there will be three years' worth of data to compare.

Lawmakers at least should get a clear picture of how the new evaluations are working, such as complaints or reports of abuse, before using them as a basis for layoffs.

And any such legislation should ensure school districts truly are keeping the best teachers -- and not just getting rid of the highest paid ones.