The psychopathology of everyday art: a quantitative Study - World ...

diagnose someone as normal who is psychiatrically unstable. The DAPA is more likely
to err on type 1, which is on the side of caution.
Variation was minimal in patient discrimination and ranged only from 95-100%
on the selected cases and from 81-98% on the independent data; but the control sample
ranged from 50-88% for identification on the selected sample and from 50-80% (although
the average was 65%) on the independent data set using the function derived from the
selected data. When the control sample size was bigger, i.e. when the function derived
from the control group of 18 was applied to the independent set of 5, it produced a better
discrimination. The sample size therefore looks like the most influential variation factor;
greater numbers should improve discrimination. The correct classifications yield is
comparable with other systems in use such as the G.H.Q. and the MSE, even though the
patient sample included some with diagnoses which were widely scattered (personality
disorder). It can be seen from the breakdown of specific differences earlier in this
chapter, the widest confidence intervals were for patients with personality disorder, they
most often spanned other groups and were hardest to identify so it is likely that the
removal of these patients would increase the effectiveness of the discrimination.
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