(NewsNation) — Today’s eighth grade students are a full year behind the eighth graders of 2019 when it comes to proficiency in math and reading, according to an analysis of test scores by the educational testing group NWEA.

The study is more encouraging for today’s younger primary school students, who have spent most of their school careers in class post-COVID. The study says that third graders are only three to four months behind the third graders of 2019.

The results are also mixed when it comes to science achievement, which is back to near-2019 levels for grades 3-5 but continues to decline for seventh and eighth graders.

One author of the study says kids who were first exposed to STEM (science, technology, engineering and mathematics) during the COVID years continue to struggle.

Also a factor: very little STEM instruction. Elementary school teachers who responded to a 2018 survey said they spent just 18 minutes a day on science, compared to about 90 minutes a day on reading.

“If science is taught at all in elementary school, it’s in the fourth and fifth grades,” said Susan Kowalski, an NWEA researcher, in comment to the nonprofit education news site The 74. “So in 2021, those were the kids who were hardest hit in science, and they are now seventh and eighth graders who have never really rebounded,” she added.

The conclusions come from NWEA’s testing of nearly eight million American students in grades 3-8.