The crucial statistic published is the percentage of pupils achieving five or more passes at grades A*-C. The results as published include all 15-year-olds, regardless of which year group they comprise.
State schools which have all of their 15-year-olds within Year 11 will find that the tables reflect fairly their performance. Independent schools which have a wider age group within a year will find the results farcical.
Rendcomb College has been particularly badly affected. The percentage of its Year 11 pupils, i.e. those sitting examinations, who obtained five or more passes at grade A* to C was 96 per cent.
The figure which appears in your table was 58 per cent because it includes 17 pupils who took no GCSEs. They could not do so; their own year groups, whether Year 10 or Year 12, would not be entered for exams.
The final insult of these statistics was to exclude two Year 11 pupils who achieved outstanding results because they were only 14 at the start of the academic year! Each year, the publication of league tables based on the Department for Education and Employment statistics has included these ludicrous anomalies. When will the DFEE simply publish the result of Year 11 candidates as indeed newspapers did back in August?