As you rightly say, this chap is very anti-GS. This is what he wrote, and what Hugh is querying.
Of the 2,155 pupils who qualified for a grammar place by scoring 121 or above in the 11-plus tests sat in 2006, 47 per cent came from prep schools in Bucks or prep schools and state schools outside the county.
The qualification rate for Bucks primary children was 24 per cent while the pass rate for prep schools in Bucks was 60 per cent.
I know that the actual figures are on the Bucks CC website somewhere, and I was sure that someone (probably Guest55) had posted a link to them, but I can't find it for looking right now!
I think the figures may be right for state school passes in Bucks. However, on prep schools the figure look slightly dodgier. It all depends on whether the figures for Prep/Out-of-County schools are based on % of those who sat the test, or on the % of the entire cohort at those schools. I am very suspicious that it is the former, which artificially inflates the pass mark. As a "sample comparison", at my son's prep school, in 2004:
Sat 11+: 39 (65%)
Pass rate: 43% or
The tendency at Prep schools and out-of-county schools would be for a child to only take the test if there was a reasonable hope of them passing, which creates a very different base number.
To compare that with state schools in Bucks, one would need the figure for the total size of the cohort and the number who actually sat the test. I recall reading on the Forum that relatively few Bucks children opt out of the test at state schools.
At the local state school in 2006 the figures were (roughly):
Sat the 11+: 58 (97%)
Pass rate: 32%
The document we need to see, if anyone can find it is:
"Analysis of pupils taking the 11+ test in order to transfer to Bucks maintained secondary schools in September 06"
The 2007 document may be out by now. I know that Drummer had a copy of the 2006 document after making an FOI request.