When I attended public school, there were no state standardized tests. Report cards were the only measure of our academic progress. I loved that. Good grades were all I had to distinguish myself.

During the SAT, my first standardized exam, I experienced disabling, heart-pounding panic for the first time in my life.

I survived. I see wisdom now in the 21st-century blend of teacher grades and state tests. That abundance of information should be good for us. But a remarkable new study from the Thomas B. Fordham Institute, a Washington-based think tank, has revealed tension between grades and test scores. And that may be hurting, not helping, the ability to judge our schools.

The most unsettling news from “Grade Inflation in High Schools (2005-2016)” by American University economist Seth Gershenson is that “from 2005 to 2016, more grade inflation occurred in schools attended by more affluent youngsters than in those attended by the less affluent.”

Are rich kids being given an undeserved boost by their spineless teachers? Gershenson, a careful scholar, merely suggests this. He offers other explanations. His data are deep but apply only to North Carolina. Those Tar Heel high school teachers might be more accommodating than the ones you had at your school somewhere else.

Gershenson got access to student data for all students taking Algebra 1 in the state — more than 1 million pupils. He compared their course grades with their scores on the state’s end-of-course Algebra 1 test.

While the grade-point average increased at all schools, it was up 0.27 points at affluent schools, compared with 0.17 points in less-affluent schools. His analysis showed grade inflation accelerating after 2011, mostly in schools with more-affluent students.

He also found that more than one-third of students who received Bs in Algebra 1 did not score proficient on the state’s end-of-course exam.

Scores on state exams, it turned out, were far better predictors of how students would fare on the ACT than the grades they got in the classroom.

But previous research shows that grades do matter when it comes to predicting whether a student will complete college. In fact, grades are a better indicator of that than SAT and ACT scores. And some advocates point to that when they encourage colleges to eliminate their entrance exam requirement.

So why are grades a better predictor of college success? Maybe because they reflect not only academic understanding but also behavior and teamwork, qualities important to reaching such goals as receiving a diploma.

Nonetheless, Gershenson’s data show that embracing just grades, as I once did, can lead to trouble.

“Grades may mislead students, parents, and subsequent educators — not to mention potential employers and policymakers — about how children and schools are performing and how well students are prepared for what follows,” he said.

When suggesting what to do about this, Gershenson momentarily became a bit irrational. He recommended that college admissions officers develop “a formal approach to account for systematic variation across schools in grading practices.” He overlooked the fact that selective college admissions officers no longer pay much attention to small differences in grades, and they do not have time to acquire doctorates in economics like the one he has.

His other ideas are quite sensible. The effort to move to individualized mastery learning — which requires students to become proficient in one subject before moving to another — has merit, he said. Even better, he suggested that educators fight to retain the state end-of-course exams that expose the worst of cowardly grading.

Once upon a time, more than 25 states had such tests. Now several, including Ohio and Texas, are trying to get rid of them. Oklahoma already has. Politicians often do that when faced with school failure.

I hope Gershenson writes more about this. Reality needs a champion, no matter how much people like me remember fondly the days when all I needed to measure myself was my grades.