A new proposal for Boston school assignments presented Saturday by a Massachusetts Institute of Technology doctoral student was essentially pushed to front-runner status by an advisory committee, as five other proposals began to fall off the table, just one month after they were unveiled.

The External Advisory Committee, appointed by the mayor, heard a presentation on the MIT proposal for the first time during a meeting Saturday morning at City Hall. Several members said it showed the greatest potential of providing equitable access to the city’s limited number of quality schools, as the panel seeks to create a student-assignment system that allows more students to attend schools closer to their homes.…