The timeline for an advisory committee’s sign-off on a plan to overhaul the city’s student assignment policy has been pushed into mid-December as the group struggles to come up with a final proposal.

The 27-member committee, made up of current and former parents as well as education entrepreneurs and nonprofit sector representatives, met Tuesday night at an auditorium inside Boston University’s College of General Studies to sift through analyses and potential models from the city’s school department.

Mayor Thomas Menino has charged the committee with the complex task of overhauling the existing system, which divides the city into 3 large school zones. The committee will meet again on Nov. 29, with Dec. 14 as a potential target date for a recommendation to Superintendent Carol Johnson, who listened to Tuesday night’s discussion from the back row of the auditorium.

After the meeting, Johnson noted that all analyses “suggest that we can do better,” despite improvements to schools such as Orchard Gardens in Roxbury and the Blackstone in the South End. “We know there’s more to do and we know the current system can be improved,” she said, adding “we do have to begin to formulate a set of recommendations that the committee believes responds to all of the concerns” involving closer-to-home schools and high quality schools in different neighborhoods.

In a PowerPoint presentation, school officials say that under the current system, more than 1 in 5 students have a less than 40 percent chance of access to a quality school, a problem “most acute” in the East Zone, which includes Dorchester and Mattapan.

School officials said the various models, which the committee asked the school department to analyze, improve the number. They include:

A 23-zone model that pairs zones that share a border. The model also sets up three citywide “magnet,” including the Marshall Elementary (which is expected to become UP Academy Charter School of Dorchester); Jackson-Mann K-8 School in Brighton, and Mission Hill K-8 School. According to the presentation, the model was also uses “one-way sub-zones,” allowing students living near low-quality schools to access higher-quality schools. Students living near higher-quality schools would be unaffected.

The second model is similar, but it pairs zones that aren’t contiguous, with one being high quality and another being low quality. The model keeps the three citywide “magnet” schools proposed in the first model. The distances students would travel would increase, compared to the first the first model, but would still be lower than the current 3-zone system.

The third model also uses 23 zones, but emphasizes socioeconomic diversity over geography, and increases the average distance traveled for students.

A fourth model has six zones and two “magnet” schools: the Marshall and Jackson-Mann. The model also has the aforementioned “one-way sub-zones.”

A fifth model is based on an MIT doctoral student’s work. Known as the “grouped school” model, it pairs lower-quality schools with higher-quality ones, and students would be able to choose between walk zone schools, or schools within a one-mile radius of the student, and the four closest schools. “For each school that is of lower-quality, a student would also receive at least one partner school choice, adjusted for capacity,” the presentation says. “In this model, some communities that have historically had access to higher-quality schools would have paired with lower-quality schools; average distance traveled may increase.” For example, the Chittick School would be paired with the Mather School, and the Murphy would be paired with the Holland.

A sixth model would pair lower-quality schools with higher-quality schools, and students would be able to choose between all walk zone schools and a partner school linked to the closest school to their house. “Average distance traveled is greatly reduced,” according to the BPS analysis. “Students in lower-performing areas would have a higher-quality partner school to select but access would be limited by capacity.” So, for example, the Murphy K-8 would be linked to the Chittick, and the Dever in Columbia Point would be linked to the Perkins in South Boston.

Bill Walczak, a committee member and former BPS parent, told school officials that some of the plans are too complex and that explaining them to parents would be difficult. The plans need to return to a simpler approach, he said, focusing on distance and quality schools.

Others in the audience raised questions about balancing choice with quality. “Quality has to be the central issue,” said District 7 City Councillor Tito Jackson, who sat in for some of the discussions. He said he is looking to see a plan that addresses the quality question as well as his concern about 25,000 or more students walking to school, navigating through the streets of Boston and some unsafe areas.

Asked about Jackson’s concern, Johnson said community safety isn’t just a school issue. “That belongs to all of us,” she said. “We all have to participate in community safety.”

Any school assignment changes would go into effect in the 2014-2015 school year. The advisory committee is expected to seek additional input before it offers a final recommendation to Johnson, who will take the proposal to the School Committee.

The school department has set up a website with information about the school assignment process at bostonschoolchoice.org.

Meanwhile, a coalition of organizations is taking aim at the overhaul process, arguing that proposed assignment plans reduce access for students from Roxbury, Dorchester, and Mattapan. The coalition, which planned to hold a meeting in Roxbury last night, includes the Black Educators’ Alliance of Massachusetts, District 4 City Councillor Charles Yancey, and several bus driver unions.

Separately, District 3 City Councillor Frank Baker is promoting a meeting next Monday (Nov. 19) that will focus on providing information to the public on the proposed school assignment reforms. The session will start at 6 p.m. at the Leahy-Holloran Community Center on Worrell St.

“The student assignment policy was last changed over 20 years ago,” Baker said in a note to District 3 residents. “I strongly encourage all concerned residents or anyone interested in our schools, community centers, and libraries to attend and get involved in this process.”