On Wednesday, the Senate Education Committee unanimously approved Simitian's proposal requiring that students starting kindergarten turn 5 by Sept. 1 of the school year. The current cutoff date is Dec. 2.
The new age requirement would be phased in over three years, beginning in 2012. Its effects would be positive both educationally and financially, Simitian said.
Last year, some 289 Palo Alto teachers sent a petition to Simitian requesting the change, saying many of the younger children they see simply are not ready for the increasingly academic rigors of kindergarten.
California has one of the latest kindergarten cut-off dates in the nation, with about a quarter of children starting kindergarten before age 5. Past legislative proposals to change the date have been unsuccessful.
Now, Simitian believes, the state may have reached a "tipping point," with both the educational and financial arguments for the change looming large.
Removing the approximately 100,000 children who would no longer be eligible to start kindergarten would save about $700 million a year, according to the independent Legislative Analyst's Office. Those savings would continue through the 13 years the children would have been in the system, adding up to $9.1 billion, Simitian said.
He proposes to take half those savings and put it toward preschool programs.
One financial concern with the bill could be that savings would not be realized in the first year because of California's longstanding policy of giving declining-enrollment districts one year's worth of revenue even though they've lost the kids to cushion the blow.
"So for the first year, we're still funding those kids without the net savings. And if we take half of those 'savings' and use them for preschool, it's a net cost. So we'll have to sort that piece out," Simitian said.
Simitian's bill allows parents of younger children to request exceptions from their local school board if they want their child to begin kindergarten at an earlier age.
When he received the petition from the Palo Alto teachers last spring, Simitian said he was struck by the fact that it was signed by more than just kindergarten teachers.
The petition was initiated by Walter Hays kindergarten teacher Diana Argenti and Palo Verde reading specialist Natalie Bivas.
"Almost every child who comes to me for reading support has a fall birthday. They don't catch up somehow down the line," Bivas said. "By third grade, teachers start asking me why we didn't hold these children back. By then, we're discussing special-education intervention."
Research indicates that beginning school at an older age improves children's social and academic development, Simitian said.
A 2005 study by the Rand Corporation found a "significant boost" to test scores, especially for children from low-income families, he said.
Based on these benefits, California's non-partisan Legislative Analyst's Office, the California Performance Review and the Governor's Committee on Education Excellence have each called for an earlier kindergarten cut-off date.
In Wednesday's Education Committee hearing, Simitian's bill was supported by the Association of County School Administrators and opposed by the California Teachers Association.