My daughter started at the local Grammar school this September. The year seven took CAT tests(verbal, non verbal and quantitative) in the second/third week. She had never done CAT tests in primary at all.
At the open evening we were given the results and they explained that they would be used to highlight our childrens strengths and weaknesses. They use them as a means to tell if your child is underperforming.
Personally I do not hold that much store by them, according to my daughters results you would think she was some sort of child genius(the school has used these results to identify gifted children, but in this case an average score of 119 qualifies- top 10%), but she has to really work hard to grasp the principles of maths. It certainly does not come easily to her. Also, she came in the top 2% nationaly for verbal reasoning, but if you saw her writing and spelling you would not think so.
They cannot measure motivation, determination, perserverance etc which play such a big part in how well a child does. But they are a useful pointer. Overall I'm pleased they sat these tests, if nothing else they have given my daughter a massive boost to her confidence