SACRAMENTO (CBS13) – Nearly three-quarters of school districts statewide require kindergarten students to go to class for a full day and a bill mandating that across California is one step closer to becoming law.

Right now, districts can choose to offer full- or half-day kindergarten; however, students aren’t required to attend school in the state until first grade.

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Assembly Bill 197 would require districts to provide at least one “full‑day kindergarten (that) is the same number of minutes per school day that is offered to pupils in 1st grade.” It would go into effect for the 2022-23 school year.

The bill passed the Senate Education Committee on Wednesday.

According to the bill’s author, “Full-day kindergarten programs close achievement gaps between young children from minority and low-income families and their peers who reside in more affluent areas. By providing a solid foundation of learning to children from all backgrounds, full-day kindergarten programs ensure all students’ academic, social, and emotional success.”

However, the bill analysis cites two studies that do not necessarily show a benefit to full-day programs.

“A 2009 Public Policy Institute of California study states that ‘research to date…has provided little evidence of long-term academic benefits beyond kindergarten or first grade.’ Further, an analysis done by the Research and Development (RAND) Corporation titled ‘Ready for School: Can Full-Day Kindergarten Level the Playing Field’ found that ‘This study reinforces the findings of earlier studies that suggest full-day kindergarten programs may not enhance achievement in the long term. Furthermore, this study raises the possibility that full-day kindergarten programs may actually be detrimental to mathematics performance and to nonacademic readiness skills.’

Schools with half-day kindergarten often offer a morning and afternoon session, which uses the same classroom, often with a different teacher. When surveyed by the Legislative Analyst’s Office, districts offering only half-day, or a mix of half- and full-day kindergarten, gave a number of reasons for not offering full-day only programs: limited classroom space, teachers preferring part-day programs, and parent preference.

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In order to address the lack of space many of these schools would have if they were to switch to a full-day kindergarten program, the bill states: “full-day kindergarten must be a priority for school districts and reserving or obtaining space for the full-day kindergarten program must take precedence over all non-class requirements.”

The 2018-19 budget provided $100 million for kindergarten facility grants, and the 2019-20 budget earmarks an additional $750 million for the same purpose.

As of the 2017-18 school year, 29 percent of districts, with an estimated 131,000 students, are still on half-day schedules, with 19 percent offering only half-day and 10 percent offering a mix of half- and full-day. The average half-day length is 3.5 hours, while the average full-day length is 5.6 hours per day.

Critics, however, say the issue comes down to parental choice.

In 2014, Governor Jerry Brown vetoed a similar proposal, saying he preferred “to let parents determine what is best for their children, rather than mandate an entirely new grade level.”

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Thirteen states, plus the District of Columbia, require full-day kindergarten.