FINAL CONCLUSIONS 431

years' work in schools and other institutions I have collected
quantitative assessments for many hundreds of persons,
both normal and abnormal. At child-guidance clinics and
mental hospitals other psychologists or physicians have
doubtless done the same. My own assessments cannot
pretend to be scientifically exact: but, in the hope of
encouraging similar reviews, I venture to summarize them
here for what they are worth.

The main groups with which I have been concerned are
enumerated in Table VI. The children consist chiefly
of boys and girls selected to form the large control groups
used in my investigations of delinquency and backward
children in the L.C.C. schools during 1913-31. With
these are included a smaller group studied intensively for a
research on vocational guidance, carried out under the
Medical Research Council and the National Institute of
Industrial Psychology : this partly accounts for the larger
number in the group aged 10-14. Those under 14 are
nearly all drawn from elementary schools. Those over 14
were either attending schools of the central or secondary
type, or else had left school; since my own work was
primarily school work, school pupils still form the majority
even at these older ages; consequently this batch is
probably of a more intellectual stamp than the general
population. The adults were nearly all young men and
women between the ages of 21 and 26. For them the data
were collected mainly at two periods: in 1910—13 I was
able to obtain assessments for a number of students at the
University of Liverpool (the results obtained with this
group were fully described in my British Association paper) ;
from 1932 onwards I have been able to make further studies
among students at the London Day Training College (now
the Institute of Education) and later at University College.
For non-academic adults I have collected data from two
small clubs of working men and women formed at Settle-
ments at Liverpool and London respectively, in which I
happened to be residing.1

1 I have very gratefully to acknowledge the assistance of colleagues at the
settlements, of students at the colleges, and of teachers and others at the
schools who assisted me.