Grade Inflation and the New PISA Scores: Is a Strong Report Card a Mirage?

The Organization for Economic Cooperation and Development (OECD) released its PISA (Program for International Student Assessment) 2025 results on September 8, and for American families the headline is blunt: U.S. 15-year-olds posted the lowest reading score in the test's 25-year history (490, down 14 points from 2022), and math performance has fallen by what the OECD equates to half a year of schooling since 2018. PISA is an international exam in reading, math, and science given to 15-year-olds across 91 education systems. No American teacher grades it, and no GPA policy can soften it. One honest caveat: the OECD notes that U.S. school participation fell short of its sampling standard this cycle, so treat the specific figures with that in mind. Nonetheless, the direction of the trend matches what domestic data has shown for years.

Here is the strange part: over the same stretch, American report cards have never looked better.

If your student is bringing home A's and B's, the national data may feel like someone else's problem. We'd urge you not to make that assumption. At our learning centers across Florida, we regularly meet students with transcripts that say one thing and diagnostic results (a full-length practice SAT or ACT taken under realistic conditions) that say something else entirely. Unfortunately, the transcript has become a less reliable measure of student performance than ever before. 

How grade inflation hides learning gaps

Grade inflation is the rise in GPAs without a matching rise in measured skills, and the clearest evidence comes from ACT's own research, which compared students' course grades against their performance on the test itself. Between 2010 and 2021, the most recent span ACT has studied, the average high school GPA rose from 3.22 (a B) to 3.39 (a B+), with the sharpest jump between 2018 and 2021, according to ACT. Math showed the most inflation of any subject: after adjusting for test performance, average math course grades climbed by roughly a third of a letter grade.

Test performance moved the opposite direction. The national average ACT composite fell from 21.0 in 2010 to 19.4 for the class of 2025, per ACT, and the College Board's class of 2025 results put the average SAT total at 1029 out of 1600. Some of that decline reflects a changing test-taking pool, since test-optional policies reshaped who sits for the exams. That is what makes ACT's grades-versus-scores research so telling: it compares the same students, and finds the gap widening between their grades and their demonstrated skills. And now PISA confirms the trend from outside the system.

One more PISA finding deserves attention from families in strong school districts: the gap between America's top readers and its weakest readers is now the largest of any participating country. Averages hide a lot. A student can sit in an honors classroom, in a well-regarded school, and still be drifting toward the wrong side of that gap without anyone noticing, because the grades keep coming back fine.

What we see when transcript meets diagnostic instrument

This is not an abstract policy story for us. It walks through our doors weekly.

A typical case: a junior arrives with a 3.7 GPA, including a B+ in Algebra 2, and sits for a full-length diagnostic SAT. The math result lands 150 points below what a 3.7 transcript would lead any family to expect. When our tutors dig into the wrong answers, the problem usually isn't the SAT's tricks or time pressure. The gaps are in fractions, negative exponents, and linear equations that should have been automatic since ninth grade but remain shaky, because course grades were propped up by retakes, homework completion points, extra credit opportunities, and generous curves.

Reading shows a parallel pattern. Students who earn A's in English class stall out on SAT reading passages. The vocabulary isn't the obstacle; sustained attention to a dense passage is a skill they have rarely been asked to practice. Andreas Schleicher, the OECD's Director for Education and Skills, made the same observation about the global decline, telling Education Week that "the shift towards digital reading" and the habit of skimming social feeds "may be compromising the ability of students to engage with complex texts."

For these students, jumping straight into test strategy would be malpractice. You cannot shortcut your way around a missing foundation. So our work often begins with several weeks of remedial skill-building, rebuilding arithmetic fluency, algebraic automaticity, and reading stamina, before conventional SAT prep or ACT prep can do its job. Families are sometimes startled by this sequencing. The students usually are not. They know which skills feel shaky. Nobody had asked them in a while.

What causes grade inflation in high schools?

None of this requires a villain. Grade inflation is mostly the accumulation of reasonable-sounding policies: unlimited retakes, no-zero grading floors, heavy weighting of effort and completion, leniency that began as pandemic-era compassion, then simply stayed. Each policy is defensible on its own. Together they detach the grade from the skill.

Layer on two newer forces. First, the attention economy: students now read in swipes and fragments, and school assignments have adapted to shorter texts instead of pushing back. Second, AI. The PISA report found that roughly a third of students use AI to draft written assignments, a habit that correlated negatively with reading performance. AI is not the root cause of this decline, and banning it is no solution. A strong student who uses AI to test arguments and refine drafts gets stronger; a struggling student who uses it to skip the struggle stops building the skill the assignment proposed to build. The tool amplifies whatever habits the student already has.

The result is a system in which a B+ can mean mastery, or can mean compliance plus partial credit plus a retake. The two are ostensibly identical, and that's what makes it a mirage: the surface looks smooth in the places where the ground underneath varies the most.

What families should do

The good news is that this problem is diagnosable, and the diagnosis is cheap.

• Get an objective measurement early. A full-length practice SAT or ACT in sophomore year – or the PSAT 10, taken seriously – functions as an independent audit of skills the report card no longer reliably measures. Waiting until a junior’s spring semester converts a fixable gap into a crisis.

• Read the subscores, not the composite. A respectable total can conceal a weak algebra foundation offset by strong reading, or vice versa. The section-level detail tells you what actual work must be done.

• If a gap appears, fix skills before strategy. Pacing drills and question tactics produce modest gains on a shaky foundation. Academic tutoring that rebuilds the underlying math and reading skills produces larger ones, and the benefits show up in coursework too, since those same foundations carry AP classes and college work.

• Treat grades as one signal among several. Keep celebrating the A's. Just corroborate them: against test data, against whether your student can read a long article without a screen break, against whether last year's math still comes easily. Strong executive function habits are often what separates students who retain those skills long after the test.

Families that  handle this well share one trait: they act on information instead of reassurance. A transcript is reassurance. Diagnostic results produce information.

Frequently Asked Questions

Is grade inflation really happening in high schools?

Yes. ACT research found the average high school GPA rose from 3.22 in 2010 to 3.39 in 2021 while average ACT scores fell over the same period, with math courses showing the most inflation. The 2018–2021 window saw the fastest grade growth in ACT's study period.

Why are my child's SAT scores so much lower than their grades?

Course grades increasingly reward completion, effort, and retakes alongside mastery, while the SAT and ACT directly measure applied skills. When the two diverge sharply, it usually signals gaps in foundational math or reading stamina that classroom grading remains relatively unchanged. A diagnostic review of the wrong answers can pinpoint the missing skills.

Does grade inflation affect college admissions?

Yes. Admissions offices know GPAs have drifted upward, so they weigh context more heavily: course rigor, school profiles, and test scores. A growing list of selective colleges has reinstated SAT or ACT requirements, and Florida's public universities require scores from all applicants. A strong score corroborates a strong transcript; a wide gap between them raises questions families would rather discover early.

When should students take a diagnostic SAT or ACT?

Sophomore year is the sweet spot. An early, full-length practice test leaves time to rebuild any missing foundations before formal test prep begins in junior year, and before scores carry admissions consequences. Waiting until junior spring compresses remediation and strategy into too short a window.

Start with the diagnostic. Score At The Top Learning Centers & Schools has spent more than 40 years helping Florida families see past the report card. Schedule a full-length practice SAT or ACT through our tutoring team at any of our Florida learning centers, and we'll show you what the transcript isn't measuring. Learn more at scoreatthetop.com.