They found cosmopolitan middle-class parents were willing to devote considerable effort to choosing the 'right' school, whereas working-class parents tended to opt for the local school. The money and time available for transport to school limited working-class choice, while immigrant families were at a disadvantage because of language difficulties.
Exam results were important, but not the main factor in choice, Stephen Ball and Sharon Gewirtz told the British Educational Research Association annual conference in Stirling yesterday.
Middle-class parents respond to the feel and atmosphere of schools, judging them on uniform and discipline and the sort of children who attend them, rather than on their positions in an examination league table.
One parent said that she would not send her child to school in trainers, while a couple were horrified to discover that their preferred school was abandoning blazers.
The middle-class parents from three London boroughs who were interviewed rejected local comprehensives and often went to great lengths to make sure that their children did not attend them. They made their choice between independent day schools or elite grant-maintained schools which were openly or covertly selective.
Mr Ball said that choice was based on more than just snobbery but was influenced by class attitudes. Whether the school was good at art, music, technology or even cricket was also important for some parents.
The researchers argued that middle-class advantage was threatened by the steady inflation of academic qualifications and the increased democratisation of schooling in comprehensives.
What middle-class parents wanted was difference, Mr Ball said. The Government's policies of encouraging parents to choose schools and schools to specialise and select pupils were not leading to a classless society.
'The middle-classes are making the most of the new opportunities which these policies offer to re-establish their historic economic advantages or newly achieved status position.'
Ms Gewirtz said: 'Playing the market demands a great deal of stamina to research, visit schools, make multiple applications . . . and that stamina is sustained by knowledge, contacts, time and money.'
She reported an interview with a woman in a large semi-detached house. The woman had visited half a dozen schools twice with her husband and undertaken a sophisticated analysis of exam results. Members of her social circle were engaged in perpetual discussion about the choice of school.
In contrast, a tyre-fitter and his wife, who lived in a council house, had not considered any school for their daughter except the local comprehensive. The man said: 'Her decision - it doesn't really matter much to me.'
Factors which helped to give middle-class parents a better choice of schools included better transport, including private cars or taxis for awkward routes, and the ability to move house.
They were able to afford coaching for entrance exams, and could send their various children to schools at a distance from one another.