Three San Diego Unified high schools — Mira Mesa High, Madison High and Canyon Hills High — will move to a block class schedule starting next fall.

The change trustees approved Tuesday evening is a scaled-back plan from the district, after community members voiced concerns at a September board meeting.

The new schedule — known as 4×4, with generally four courses per day each semester, rather than six year-long classes — will let students take more classes overall throughout their career.

Deputy Superintendent Nicole DeWitt had said previously that the three schools were looking at a hybrid 4×4 schedule that would let some classes, such as Advanced Placement, be yearlong.

The growing number of courses that San Diego Unified students must take in order to graduate has been a driving factor in the changes.

The district’s original plan was to have even more schools try out different forms of the 4×4 schedule.

But at a meeting last month where people spoke out against that plan and administrators and trustees expressed confusion about it, a vote was postponed, and the plan was scaled back.

Under the plan approved Tuesday, other schools that aren’t part of the initial effort can decide whether a 4×4 schedule would meet their needs in the following years.

If they decide it doesn’t, the district says, schools should design schedules to give students chances to complete multiple career and technical education pathways.

On Tuesday night, principals and instructional coordinators from the three schools described the community engagement they’ve already undertaken on it.

At the September meeting, some community members voiced concern that the changes would lead to less instructional time per class.

The leader of the district’s teachers union also objected, criticizing what he called a top-down approach to implementation. DeWitt said the district and union are in active bargaining.

Fewer people spoke at Tuesday’s meeting than the last one, but more speakers spoke in favor.

“The 4×4 schedule has made a big difference for students like me,” said Chloe Fernandez, a 10th grader at the San Diego School of Creative and Performing Arts. She said the schedule helps her find the balance between her academic classes and dance.

But parent Shaun Hunter raised concerns about implementation, including the timeline. “My daughter has to pick classes, as mentioned, very soon,” he said.

Much of the research around the benefits and drawbacks of different types of class schedules is outdated and inconclusive.

But researchers who spoke with The San Diego Union-Tribune recently said a block schedule helps students facing many graduation requirements, as is the case in San Diego Unified.

Sarah Fine, a professor of education at UC San Diego, also pointed out that longer class periods can lend themselves to deeper learning.

The district plans to collect, analyze and learn from its own data on the class schedules.

Trustee Shana Hazan said the district’s recent improvements to its data-tracking systems will now allow it to evaluate the success of the 4×4 schedules. She hopes to measure whether the schedule change makes students more motivated.

A pilot implementation of the new block schedules will begin for Mira Mesa High, Madison High and Canyon Hills High next school year, along with data collection and monitoring.

The year after that, in the 2027-28 school year, the district will keep monitoring things and will produce a report on the pre- and post-implementation data.

And in the 2028-29 school year, the rest of the district’s high schools can decide if the 4×4 plan will work for them.