Members of both parties, President Barack Obama and educators have hailed the new Every Student Succeeds Act (ESSA) as a sound way to replace the burdensome demands of No Child Left Behind.

They particularly welcome the opportunity for states and local districts to develop their own systems for school improvement rather than being required to use federal models.

However, one of the first initiatives being proposed by State Superintendent of Education Molly Spearman might be a move in the wrong direction. At the very least, it needs to be fully analyzed and justified before the State Board of Education approves it.

Ms. Spearman announced last week that she wants to change the way teachers are evaluated. Under No Child Left Behind, students’ academic progress, as measured by standardized testing, was one factor in grading teacher performance. Many teachers objected to the tool as unfair because some students are more difficult to teach than others and more likely to score poorly.

However, the measure was not the final grade in isolation, but the amount of progress students made.

That seems to be a reasonable benchmark. Even the poorest students should be making progress.

Ms. Spearman’s office says instead of “high-stakes testing,” student growth will be measured throughout the year as part of teachers’ evaluation.

Clearly students should be tested during the year to ensure that they are learning adequately. And clearly their progress on those tests is in part a reflection of their teachers’ performance.

But the system must ensure that testing throughout the year is rigorous and that it measures how well each student is learning. And “high-stakes” tests must not be disregarded, as they are, after all, an indication of student progress. At the end of the year, if a student has not shown expected progress, his teacher should be held partly accountable.

Teachers have traditionally been assessed by their principals and peers. That would be a bit like a company deciding what to pay a salesman based on how his coworkers think he’s done instead of how much he has sold.

If that had been working well, South Carolina’s schools wouldn’t be among the lowest ranked in the country.

Ms. Spearman expects to present her proposal to the State Board of Education in January. Any system for teacher accountability must be fair and tough.

South Carolina doesn’t need another way to shortchange its students.