Using data collected by state and community colleges, testing experts on a state committee determined last year that a 75 on the English Regents and a 80 on the math Regents roughly predicted that students would get at least a C in a college-level course in the same subject. Scores below that meant students had to often take remediation classes before they could do college-level work. Only 41 percent of New York State graduates in 2009 achieved those scores.

In the wealthier districts across the state, the news is better: 72 percent of students in “low need” districts are graduating ready for college or careers. But even that is well under the 95 percent of students in those districts who are now graduating.

The data also cast new doubt on the ability of charter schools to outperform their traditional school peers. Statewide, only 10 percent of students at charters graduated in 2009 at college-ready standards, though 49 percent received diplomas. The state has not yet calculated results for every district and school.

State officials have also begun a series of meetings in local districts to introduce this data and ask local officials what they want to do about it. A common reaction, Dr. Tisch said, is shock and hesitancy. There are fears of plummeting real estate values, as well as disagreement, particularly in rural areas, with the idea that all students need to be prepared for college.

Jean-Claude Brizard, the schools superintendent in Rochester for the past three years, said that while he was surprised by the data, he welcomed the effort to move the conversation away from simply graduating. In an effort to improve, Rochester has closed half its high schools and opened new schools, including its first high school that allows students to earn credits at several local colleges.

“We are behind the eight-ball a bit, but we are pushing,” he said. “It’s shocking, I know. It’s low. But for me, it is going to support my initiatives.”

In New York City, roughly 75 percent of public high school students who enroll in community colleges need to take remedial math or English courses before they can begin college-level work. City education officials said the 23 percent college-ready rate was not a fair measure of how the city would do if graduation requirements were raised to a higher standard, because students would work harder to meet that new bar.