Cambridge Public Schools Superintendent Jeffrey M. Young proposed during yesterday’s school committee meeting the establishment of a middle school in the city’s K-8 school system to close the achievement gap among different socioeconomic and ethnic groups.

“Not every child is getting exactly what they need,” he said, describing the distinct gap between white and Asian students and other groups including low-income students and those with special needs as “immoral.”

Young advocated accelerating the improvement of under-performing groups while continuing to support white and Asian students, as well as expanding the student body to close the achievement gap. Currently, eight of the 11 K-8 public schools in Cambridge have fewer than 400 students.

“When school size is too small, it forces both students and teachers to reside in a small marketplace of ideas,” Young said, adding that the current system may hinder development if teachers protect students so much that they cannot “rise or fall.”

Young’s presentation came after a five-month process of collecting data and engaging members of the community.

For decades, the committee has expressed a concern about the quality of education 6th-8th grade students receive in the city’s K-8 schools. Critics say that the system, which lacks a traditional 6-8 “middle school” environment, does not meet the needs of students in early adolescence.

When Young was elected, he agreed to provide concrete recommendations regarding “the middle school issue” within the first a hundred days of his tenure.But in September he announced that he would need more time to adequately prepare.

Young’s long-awaited proposal consisted of five different options, including keeping the K-8 system and replacing some K-8 schools with K-5 elementary schools and a new middle school. The latter option, which Young said he favored, provides parents with a choice of enrolling in either system.

School committee members received Young’s proposal yesterday with some reservations.

Committee members Patricia M. Nolan ’80 and Marc C. McGovern both said that they would need to review more data to determine which option would best address the school system’s issues.

McGovern added that he is not convinced that the district is unable to close the achievement gap with a K-8 system.

Young’s proposal to create a middle school was met with noncommittal support from others present in the meeting.

Cambridge Teachers Association President Chris Colbath-Hess said she did not favor any option above the others, as the proposals are still in their preliminary stages, but reaffirmed her commitment to address the discrepancy among students.

David P. Maher, a City Council member who is running for Cambridge mayor, agreed, adding that he would withhold judgment until details are finalized.

Young is scheduled to give a more detailed presentation of his model on April 6, and the school committee will vote on the plan in May.

—Staff writer Rediet T. Abebe can be reached at rtesfaye@college.harvard.edu.