"We have not unlocked all the mysteries," said Marco Petruzzi, Green Dot's chief executive. "We're very humble about that."
Byron was kicked out of a Pomona high school two years ago for fighting. He moved in with his father near Locke in part, he said, to escape bad influences, including some in his family. Last year, he got Bs and Cs and he flunked a class.
"Last year it didn't matter," said Byron, who earned A's and Bs this year. "I never had nobody on me like I do now. This year, any class I decide to mess in, I will get in trouble with the teacher. They don't expect me to mess up."
Green Dot replaced most of the old Locke faculty and split the school into eight smaller academies. Much of the staff is young, and only 15% have fully completed teacher credentialing requirements. Half have taught for three years or less. And half are 28 or younger.
But many make up in enthusiasm what they lack in years. Bridger regularly spends 12 hours a day on campus, typically arriving just after 6 a.m. When school ends, some students remain seated in her classroom and others file in for extra assistance, to make up work, to help Bridger with projects or just to hang out.
The school's youth-oriented staffing allows Green Dot to pay higher starting salaries while still maintaining a payroll that averages below traditional public high schools in the area, according to a Times analysis.
Even before Green Dot, Locke had a contingent of energetic newcomers and capable veterans. The math department rebuilt a dormant calculus program, and 44 students enrolled in the class this year.
But the motivated teachers, experienced or not, received inconsistent support, which accelerated burnout, disillusionment and departure, said calculus teacher Fernando Avila.
"This became the place where a lot of teachers not performing in other schools ended up," Avila said.
Teacher Elijah Woodson said the achievements of the prior staff are underappreciated. Against the Green Dot takeover all along, he nevertheless stayed on after Green Dot asked L.A. Unified to continue to provide teachers for students with disabilities. That will change next year, in part because Green Dot managers are dissatisfied with the way L.A. Unified handled the contracted teachers.
Woodson said he feels personally harassed, with administrators regularly observing and evaluating his teaching. During one visit they focused on a student who was asleep in class -- because of medication, Woodson said -- rather than on 20 others who were paying attention.
Being critiqued is something Green Dot employees must get used to. Bridger said she relies on observations to improve, although not all teachers report favorably on their administrators. And the Green Dot teachers union filed several grievances over pay and working conditions.
Some classes have exceeded 40 students, a dilemma for Green Dot, which prides itself on small classes. And although the staff has made a concerted effort to keep students in school, some have dropped off the radar. A few with serious discipline or attendance issues have recently been sent home.
To make classes more manageable, administrators have enrolled some especially challenging students in Locke 4, an academy whose Opportunities program consists of three classrooms set aside for students who are doing poorly or displaying serious behavior problems. The program also accepts students returning after being convicted of crimes.
On a recent Monday, 14 students sat in an Opportunities class with one teacher and an aide -- Green Dot wanted especially small adult-to-student ratios for these youths. The posted class rules were simple: Stay seated during class; complete all of your work; be polite and respectful.
These expectations failed to achieve traction with several students, including a recently arriving freshman.
"Do you need help?" the teacher asked him.