In fact the second and third patterns are far more likely than the one you report Demos as having arrived at. There is clear evidence that a minority of young people are socialised into crime (by older youths) at about 12. Serious truancy tends to come later, and exclusions result from the importation of criminal behaviour towards other pupils into school. Since exclusions follow crime, they cannot be a cause of it. The school's prime responsibility is to protect pupils whilst they are in school. That may include protecting them against other pupils.
The location of a school is no longer a guide to the type of areas their pupils are drawn from. Two schools geographically close often enrol very different segments of the local population of young people.
E F SMITH, Headteacher, Churchfields High School, West Bromwich, Sandwell, West Midlands