With age standardisation does there have to be a minimum number of children for each birth month to get valid results? If for instance there were only 5 children april born could you get valid standardised results from this. For 11 plus entry obviously there are large numbers sitting but how do areas such as Bucks age standardise for other age entry, 12 or 13 plus, when the numbers will be much smaller. CRGS 's recent 13 plus only had 40 boys sit, is it possible to age standardise such a small cohort?
Many of the schools set their own 12+ and 13+ tests now in bucks, I know rgs was not standardised last year for the 12+ The year at secondary school forces a level of maturity really, that maturity does not kick into action at primary, but I hazard a guess that by 12 things have mostly levelled out. Home environment will be less of an influence too, as the children find what their peers are reading, watching, talking about far more important.