Kudos to Mercedes White for writing a balanced account of competing perspectives on granting teachers tenured status and evaluating the quality of the work they do. ("Teacher tenure at issue in improving education," Dec. 19.) Ultimately, the issue breaks down to two questions:

Does it make sense to extend a teacher a guarantee of continued employment (tenure) after just a few years of teaching — no matter any subsequent deterioration of performance or effort? The answer is no. No workplace could succeed with such a forfeiture of quality control.

Should student achievement be a major consideration in holding teachers accountable for their work? Absolutely. And as the Gates Foundation points out, value-added assessment (sometimes called the "growth" model) is the fairest tool to use. It shows how much students progress over a year or more under a specific teacher. That way, teachers are not penalized for accepting a challenging assignment with underachievers. In fact, they may well be rewarded as their students steadily gain essential knowledge and skills.

Robert Holland

Senior Fellow for Education Policy

The Heartland Institute

Chicago