"In lessons involving direct instruction, teachers can teach 40 or 50 students as easily as 20," Mr Bowden said. "But with numeracy, for example, we know these 10 students need remedial work and one teacher can take them aside while a different teachers takes all the students who are on track. "It's a recognition that students learn at difference paces." Schools should either move all classes to a composite structure, or none, Associate Professor Linley Cornish said. "Schools only having some composite classes sets up a stigma, and parents start to think, 'should my child be in a different class, is my child being disadvantaged?'," she said.

http://www.smh.com.au/national/education/composite-classes-on-the-rise-as-some-schools-go-even-further-20170517-gw6jdp.html