Glasgow secondary heads are advising the Inspectorate to reconsider plans to use postcodes as a basis for grouping schools under ministers' target-setting agenda.
Ian Valentine, president of the Glasgow branch of the Headteachers' Association of Scotland and head of Cleveden Secondary, warns that postcodes are "massively misleading", a point also made by Aberdeen City Council in its submission.
Mr Valentine says a "Kirriemuir solution" fails to take account of the complexities in urban Glasgow which has a huge movement of pupils across the city. More than half the pupils at Cleveden are on placing requests as are more than two-thirds at nearby Hillhead High.
Mr Valentine said: "Our school is situated in G12 but only a quarter of pupils come from G12. It will have a very large percentage of adults with post-school qualifications. The biggest proportion come from G20, which is the Maryhill-Ruchill corridor, and it probably has the lowest percentage of parents with post-school education."
While supporting the target-setting approach, and the use of figures on free meals, the heads urge the Inspectorate to introduce a "weighted average" for each school based on postcode intake.
Aberdeen has noted that one of its most disadvantaged schools is next to the university.