However, only recently has the Department for Education and Employment provided a breakdown of progress by individual local authorities.
Overall, 128 of the 149 LEAs in England with secondary schools did better than the previous year in the overall percentage of pupils gaining five or more grades A*-C.
Disappointingly, 19 LEAs saw a decline in the percentage of their pupils achieving these grades. But, in most cases the decline was small and in only two authorities did it reach 3 per cent.
More worrying is the apparent gender gap in achievement. In 33 LEAs there has been a decline in the percentage of boys gaining top grades as comparedwith only 20 LEAs where there was a decline in the performance of girls.
As with the overall figures, the level of the decline in performance by either boys or girls was normally a small one. In more than half of the LEAs it was only 1 per cent or less. However, in one LEA, Greenwich, boys' performance dropped by 9 per cent.
One factor that may partly account for the poorer performance of some LEAs is the incidence of over-sized classes. A quarter of the LEAs where overall performance declined had an above-average incidence of secondary classes of 31 or more.
Moreover, six local authorities were in areas where increasing teacher vacancies may have contributed to a decline in pupil performance.
The author is a director of Education Data Surveys. His email address is email@example.com