School is largely back in person -- to the relief of just about everyone with even a passing connection to the country’s educational system.

During the pandemic, parents, teachers, and students frequently lamented the inadequacies of online learning, and for good reason. Virtual classrooms were often pale imitations of their real-world counterparts.

But it's worth asking -- were things all that great before? A 2018 national survey found that nearly three-quarters of high schoolers were both stressed and bored while at school. Nearly one-third reported that they were bored during most or all of their in-school hours.

Now that kids are back in school in person, we should use the experiences of the last year and a half to help us reimagine the classroom. The key to this transformation lies in a method known as mastery-based learning.

The world has changed quite a bit since our grandparents went to school. Yet the default mode of public education, and the content kids learn, hasn’t changed much in the past century.

Most curricula are designed to be one-size-fits-all, aimed at ensuring students acquire "grade-level" skills regardless of their abilities and interests. Few students end up with a perfect fit.

A mastery-based approach, on the other hand, encourages students to dive deeper into topics they find interesting and learn at their own pace, whether that happens to be faster or slower than some age-based benchmark.

Ample research demonstrates the model's potential. Hundreds of studies have found that mastery learning can boost achievement, improve student confidence, and make them more enthusiastic to learn. The typical student in a mastery-based setting performs as well as the top 15% of students in traditional learning environments.

At its core, mastery learning prioritizes the acquisition of skills and concepts over content. It allows each student to fully master a skill before moving on to new material. And it encourages students of different ages to work together based on their learning styles, interests, and levels of understanding.

Mastery-based learning also offers tremendous flexibility to teachers. The model encourages them to use real-world events to help students stay engaged instead of simply relying on a fixed curriculum.

At the Mysa School, for instance, we used the COVID-19 pandemic as a starting point for lessons in chemistry, biology, and statistics. Our kids learned about history and government through the lens of the Black Lives Matters protests. And during last year’s Census, we tasked our students with conducting a census of their own neighborhood with the goal of developing their math, civics, and social studies skills.

Since mastery-based learning personalizes education for each student, teachers can also use children's unique interests -- in dinosaurs, soccer, comic books, or anything else -- to convey concepts and ideas in ways that get them excited.

Some have argued that mastery-based learning mainly helps students already poised to perform well. But the mastery approach is explicitly designed to meet students where they're at.

By contrast, our current system of age-based, teacher-driven learning passes students to the next grade even if they've only met a bare minimum -- setting them up for future struggles. On the flip side, rigid adherence to state or district curricula discourages students from exploring subjects they’re interested in more deeply. That move to effectively cut off learning could compel students, especially those on the margins, to disengage from school.

Kids also learn better when they’re into something. Consequently, a mastery-based approach can enable students to learn more efficiently -- and still have time for lessons or subjects they have trouble with.

The individualized approach underlying mastery learning might seem to be too complicated for all but the smallest schools. But public school systems in at least nine states -- in districts ranging from urban New York to rural Alaska -- have implemented the model, with promising results.

The pandemic offered parents a crash course in how our educational system really works. As we return to the classroom, we have an opportunity to reevaluate old ways -- and embrace a model that keeps students challenged, engaged, and motivated.

Siri Fiske is the founder and head of Mysa School in Washington, D.C.