New York City Mayor Michael Bloomberg set off a fracas last week when he said that class size didn’t matter at all -- as long as the right teacher is in front of the classroom. He was talking about elementary and secondary schools, but the resulting criticism might well be heard if someone made the same remark about college instruction. Colleges, after all, boast about small student-to-faculty ratios, and viewbooks show case seminar rooms and laboratories, not the giant lecture hall. At a session here at the annual higher education meeting of the Southern Association of Colleges and Schools, officials from Virginia Tech tried to challenge the audience’s assumptions that large classes are necessarily bad learning experiences.