There must have been a number of influences working in the minds of the original pioneers of the eleven plus.
It does seem possible that the work of a man called Roberts, who in 1940 tried to find evidence of intelligence, may have contributed to the early pre eleven plus debate. He tested 3400 children of school age. He looked at the siblings of the top 4% and the dullest 4%.
He found that 63% of the siblings of the brightest were bright. 6.6% were dull.
3.7% of the siblings of the dullest were bright and 56.3% were dull.
We do not need to replicate these tests today. All we need to do is to find 3400 grandmothers.
Question: Are all your grandchildren as bright as each other?
Answer: Of course they are. Little Chloe, who is only two, is going to be the brightest of the lot.
Question: Will any of your grandchildren pass the eleven plus?
Answer: Of course. My son did, my daughter did and all their children will pass.
Question: Who is the most intelligent person in your family?
Answer: What an impertinent question. I am of course.
These question and answers will not provide a satisfactory basis for any current discussions about the eleven plus. They will show, however, that it is almost impossible to forecast that because one member of the family has won a place in a grammar school, it does not necessarily follow that all the rest will. Parents are remarkably resilient, however, and will keep trying to do their best.
(The grandmother mentioned above may possibly have been a highly respected member of the community – and a demon at bridge as well as a tough tennis opponent. You just never can tell.)