In sometimes tense exchanges, the nine parents demanded a greater sense of urgency by the school district in fixing what they called Palo Alto's "bifurcated school system one for the wealthy and one for the economically disadvantaged."
"When Visalia is doing a better job (helping black students master Algebra 2), folks, you are at the bottom," parent Michele Dauber told the board.
The statistics came from a print-out by Dauber's husband, Ken Dauber, of results of the 2011 California Star Test in Algebra 2 for various student subgroups.
Seven percent of Palo Alto's black students who were tested showed "proficient or above" placing Palo Alto 147th statewide in the category. The best district in this regard Hawthorne in Los Angeles County had 75 percent of black students who were tested showing "proficient or above" in Algebra 2.
In both cases, the number of students tested was small 15 in Palo Alto and 12 in Hawthorne.
Superintendent Kevin Skelly did not quibble with the data, though he said he would "have someone look at it."
"I didn't get into education to have results like this, and we need to work to have them better," he said.
Palo Alto long has struggled with the achievement gap, publishing student data and agonizing over how to fix it.
The district has launched multiple early-intervention efforts to nip problems in the bud; analyzed student profiles; trained teachers in culturally sensitive instruction methods and established a special "college bound" program at Barron Park Elementary School featuring a longer school day and longer school year.
Last year Skelly proposed boosting the district's graduation requirements to match the academic prerequisites for the University of California and California State University systems. The proposal is seen as a way to boost expectations and results for low-income and minority students who perpetually lag behind the district's high averages.
But the proposal was tabled after an outcry from parents of special-education students, who worried their children would suffer under the suggested requirements.
The recommendation also was opposed by the Palo Alto High School math department, which argued that some students cannot pass Algebra 2 (required for entrance to University of California and California State University schools) without a watering down of the curriculum, which the department said it was not prepared to do.
The so-called "Paly math letter" has become a rallying point for minority parents as well as for the Daubers' group, We Can Do Better Palo Alto, which has lobbied for measures to reduce academic stress.
The groups have demanded that both high schools offer basic no-frills "lanes" in math and science that meet, but do not exceed, the UC/CSU entrance standards.
Parents of elementary students said they are fearful of a system that sees many black students placed into special education by the time they are in middle school. The district is currently under state sanctions for having a "disproportionate" number of underrepresented minority students in special ed.
"My two sons are at Nixon, doing fantastically well with teachers and a principal who have high expectations for them," parent Kim Bomar said.
"But I'm concerned about what the parents of other children say, and what will happen to (my sons) when the get to the crucible ... of Paly."
The issues are expected to return to the board in the next two months.
Tuesday night, board members pleaded with the angry parents for a "safe environment" in which people are able to air different opinions.
"I hear the anger and the frustration and the concern in the questions and comments, and they're legitimate," board member Barb Mitchell said.
"But I want to avoid an atmosphere where people don't feel safe expressing their points of view."
But parent LaToya Baldwin Clark said, "Civility goes only just so far.
"This is a conversation that's been going on at least five years, and there's been very little progress, especially for black children in this district," Clark said.
"The way I see it, the people who should feel most 'unsafe' are the parents who are suffering under this dual system.
"And when we want to talk about it, we get a lecture about civility."
Clark suggested that the district scrutinize "teacher profiles" in addition to student profiles.
"Find out which teachers are really getting kids to learn."
She cited herself the daughter of teen parents without college degrees as a "testament to the fact that any kid can learn."
"I went to a school where teachers believed in me despite my background," she said, noting she completed BC Calculus in high school.
"It wasn't 'til I went to college that I realized there were teachers out there who didn't think black and Hispanic and poor kids could learn as well as anybody else."