"What we're doing is buying their time back to make them feel uncomfortable," said Myers, who said students are told to use the time productively, preferably doing school work.
They can't talk, play games or sleep, he said.
Students don't like having to give up their free time, said Myers, who uses statistics to prove his point.
During the first year of the program, the number of referrals dropped 35 percent, with a corresponding 27 percent decline in out-of-school suspensions, he said.
So far this year, the numbers are running a little above last year, he said.
However, they're still much lower than they were before the program started. Myers said most referrals now are for habitual tardiness - a hard-to-solve problem - rather than for the more serious offenses he used to see.
"The school climate is better because of that," he said.
The progressive discipline policy defines the consequences for students' actions, putting the onus of responsibility on the student, who usually has plenty of chances to avoid a three-hour Saturday School stint.
It takes a serious offense, such as truancy or smoking on campus, to be sent directly to Saturday School, Myers said.
Less serious offenses, like breaking a class rule against chewing gum, would get a student a half-hour detention with the teacher, he said.
But the stakes keep going up if the student either doesn't serve a detention or repeats the offense, Myers said.
Students who miss Saturday School end up with two days of out-of-school suspension, he said.
For violent offenses, such as fighting, students automatically receive out-of-school suspension, he said.
The policy was implemented when the school switched to "block scheduling," giving students four 1 1/2-hour periods a day instead of seven 45-minute periods, Myers said.
If school officials had continued the "in-school suspension" system, students would have lost two days of classes for each day of suspension. Myers said.
The old system also left a longer gap between action and consequences, he said. And it penalized teachers, who had to come up with special assignments for their students.
Myers said he could have opted to send his students to a county-wide Saturday detention program for middle and high school students.
But Myers preferred to keep his students in the school, where he can monitor the program.