One one hand CEM says the tests are based on national curriculum, do not need tutoring and on the other hand they include words that are unlikely to be taught in the KS2 national curriculum ?
Like spellings, does the national curriculum define a word list that all children should know by KS2 ?
The new national curriculum does not contain a list of words children should understand that an 11 plus test provider could then use as a bank for their vocabulary type questions. Gl assessment, through its various testing arms, probably has for certain words a rough idea of the percentage of 11 year olds who have certain words in their receptive vocabulary.
When loads of schools were going cem last year, it was the reported emphasis on vocabulary knowledge in the final result, and the apparent repetition of some of the words used, that made me feel very sceptical of some people's opinion that cem exams are a more reliable and fairer test of ability than gl. I didn't get it then, and I still don't.
Bucks was odd in just having vr, but they could have commissioned a more broad ranging test if they chose to.
I do not know how gl or cem could select vocabulary which would be the preserve of the rather erudite child and assume this is an ability measure rather than knowledge a child has gained due to being in fortunate circumstances of some sort.