Chester E. Finn Jr., a Hoover Institution senior fellow and former assistant U.S. education secretary, is the author of “School Accountability: Past, Present & Future.”

President-elect Joe Biden’s yet-to-be-named education secretary will immediately face a difficult question once in office: Should states, for the second year in a row, be given waivers from their annual obligation to assess every student’s reading and math progress in grades 3 through 8? Biden has indicated that, in matters such as pandemic-fighting, his administration will look at the data and follow the evidence. That approach should also apply in education.

The waivers granted by Education Secretary Betsy DeVos this past spring made sense at the time. As the coronavirus pandemic worsened, schools were closed and there was no practical way to administer the assessments required by the Every Student Succeeds Act of 2015. Most states also suspended their own end-of-course exams, graduation requirements and other important standardized measures of student learning.

But don’t think for a moment that such diversions of the student data stream are without cost. The results from those state assessments are the main source of information about school performance and about pupil learning in the core subjects of the K-12 curriculum. The results also indicate whether America’s appalling — and persistent — achievement gaps are getting any narrower.

These student statewide test results are the foundation of a school-performance measurement structure that the United States has been painstakingly constructing in the decades since being declared “a nation at risk” in 1983.

The information from the tests is used at every level of the system. It enables parents to see how their children are faring on an “external” metric, beyond the grades conferred by their teachers, and it helps principals assess how their schools are doing. The results also equip superintendents to gauge what must be done to boost district-wide achievement, and they furnish state officials with the information needed to guide their assistance and interventions.

That doesn’t mean these tests are popular. They’re a bother for students. Teachers are tempted (and sometimes prodded) to focus too much of their instruction on what will be assessed. Teachers’ unions hate the spotlight the tests shine on school performance and teacher effectiveness. Administrators find the tests a hassle to administer effectively, and they worry that their school’s scores may lead to embarrassment and intervention. State education leaders struggle with what exactly to test, how best to report the results, and what to do about struggling schools and poorly performing school systems.

Honestly, pretty much no one likes them. No one much likes check-ups with the doctor or dentist, either, no matter how useful they might be. Yet, after last spring’s school shutdowns and the forced — and mostly ill-prepared — transition to online learning, U.S. education may never have had a greater need for reliable information about how students are doing.

What have they learned, and not learned, during these difficult past several months? Which schools and districts moved effectively to virtual education? How did achievement gaps change according to family income or racial group?

Lacking such data, schools were inadequately prepared to do right by their pupils when they opened (or didn’t) in the fall, and districts and states were in the dark about which schools needed help. As for families, they’re back to relying upon their teachers’ red pens, which give an important, but incomplete, picture of performance.

As the weather grows cold, the pandemic worsens and more schools close again or go all-virtual, nothing about education is going to get better until well into next year, when, with luck, a substantial part of the U.S. population will have access to a coronavirus vaccine.

The 2020-2021 school year is likely to set a record for ineffectuality. Tens of millions of young Americans are going to emerge from it with pronounced learning deficits. The year is all but certain to end with wider gaps than when it began.

But how will we know for sure if end-of-year tests are again suspended? How will parents and teachers know which students need the most catch-up in which subjects? Who has the greatest need for summer school or tutoring? And how will district and state leaders know which schools coped better and worse?

If all goes well, next fall, schools will open with a semblance of normalcy. But flying blind about student performance until then is indefensible. An educational disaster has been developing, unmeasured, since the spring. The nation’s incoming education secretary should commit to the 2021 spring assessments and do everything possible to ensure they happen. Otherwise, America won’t know how bad the damage is or what needs fixing.

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