Randi Weingarten, president of the American Federation of Teachers (AFT), proposed a “bar exam” for public-school teachers in a Wall Street Journal op-ed last week.

Modeled after the bar exam for aspiring lawyers, the new test would be intended to produce highly effective teachers. But it would do nothing of the kind.

As we have explained before, passing a certification test has no impact on a teacher’s effectiveness. These tests are just barriers to entry that would discourage high-quality people from entering the profession in the first place. Existing teachers stand to benefit from these barriers, since they would limit competition and potentially push up wages, but students and taxpayers would certainly not benefit.

A number of WSJ readers saw the problems with Weingarten’s proposal and sent several excellent letters in response. What follows is a sampling of those letters edited to emphasize the best parts. To read all of the letters in full, click here.

The proposal by Randi Weingarten to ratchet up the credentialing and licensing requirements of teachers by instituting a bar exam for teachers is a colossally bad idea. As has been demonstrated time and again, there is no evidence that teacher credentialing increases student achievement. What the evidence suggests is that teacher-certification requirements actually drive potentially good teachers, especially individuals with advanced subject-matter knowledge, out of the teaching market.

Tim Keller
Institute for Justice
Tempe, Arizona

The president of the American Federation of Teachers tells us that there are too many unqualified teachers and that we should impose the equivalent of a “bar exam” for new K-12 teachers. So, the first thing we do is grandfather in the problems (oddly enough, this proposal doesn’t apply to existing teachers). Creating hurdles to teaching reduces supply, and if demand is the same, it raises costs to the school district and thus tends to push up the pay of the existing teachers. Not surprising that a union leader is proposing to set up additional barriers to entry.

Professor Ronald D. Rotunda
Chapman University
Orange, California

Randi Weingarten overlooks the predominant difference between the teaching (union) and legal (nonunion) professions: individual responsibility. When lawyers don’t meet employer or client expectations, their employers and clients are free to terminate their relationships. There are no grievance processes standing in the way. Nor do lawyers who excel at their jobs go on strike and refuse to work, march through our cities and towns demanding more money and more time off, or advocate for more protections for their underperforming counterparts.

Scott Emery
New York

Is this the same Randi Weingarten of the AFT who opposed using standardized test scores as part of a teacher-evaluation system in Chicago but now wants to implement a standardized test system for a teachers’ “bar exam”?

Tom Van Kleef
Fort Worth, Texas

I wonder if along with a bar exam there will be a law banning practicing education without a license. Home-schoolers will love that one.

M. R. Gedge
Hamden, Connecticut