The May 12 editorial “Sabotaging the Common Core” excoriated teachers unions and asserted that their “critique about process is a straw man for the main objection: use of test results as a factor in evaluating teacher effectiveness.”

On May 13, a news article, “When test scores reflect badly on good teachers,” presented research findings that questioned the use of such data for identifying quality teaching. The study corroborated that statistical algorithms called “value-added models” are not a reliable measure of teacher evaluation.

The American Statistical Association, hardly a handmaiden of the unions, “urged states and school districts against using VAM systems to make personnel decisions, noting that recent studies have found that teachers account for a maximum of about 14 percent of a student’s test score, with other factors responsible for the rest.” Saboteurs as well? Hardly.

Joan Baratz Snowden, Washington

The writer is former vice president for assessment at the National Board for Professional Teaching Standards and a former director of educational issues at the American Federation of Teachers.

The opposition to the Common Core State Standards by two prominent unions is a cause for concern when many of our students graduate high school unprepared for college or a career. But when some of that opposition is rooted in flawed implementation, states must address legitimate educator concerns without letting progress stall.

In Delaware, where a recent survey found that nearly 80 percent of educators support the standards, we created a comprehensive but voluntary teacher support system, assisting educators with curricula while respecting local control over teaching the standards. We also worked with our union to delay the impact of the more difficult Common Core-aligned assessments on teacher evaluations by a year while finding other ways to keep our commitment to measure student growth for those evaluations.

The standards will be much more effective if they succeed throughout the country, allowing states to compare results and drive each other to improve. Just as establishing the Common Core was a collaborative effort, we must commit to working together on the much harder task of implementation.

Jack Markell, Dover, Del.

The writer, a Democrat, is governor of Delaware. He co-chaired the Common Core State Standards Initiative.

Research finds “little or no correlation” between teacher performance and student test scores. If this counterintuitive finding reflects reality, it raises the politically incorrect notion that family reform, not school reform, should be society’s principal focus.

If even excellent teachers can’t improve the test scores of students raised in homes without Dr. Seuss books and parents willing to read them, shouldn’t public policy work to discourage such ill-prepared parents from having children in the first place?

No school or school district can ever be better than the families it serves. The sooner policymakers embrace this truth, the better chance our nation will have of salvaging its prospects for the 21st century.

Darren McKinney, Washington