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

The DDS (1988) study was an exploratory study which described an evaluation
procedure applied to the pictures of 3 diagnostic groups of patients: Dysthymia,
Depression, Schizophrenia, and one non-patient group within a population size of 239.
In order to evaluate it properly, it would be necessary to know the sizes of the sample
groups, since the detection of 100% accuracy in one sample may refer to a different
number than another group. There were indications within the text that the control group
was in some way abnormal or small.
The instrument itself rated up to 23 categories for each of three pictures by each
patient. Some categories were reduced to 2 binary variables, and some with 3 or more
choices were reduced in some other way that was not explained. The text indicated that
there were then 36 variables in the end for each picture giving a patient profile of up to
108 variables between 3 pictures, treating the repeated measures as independent. This
procedure was not well explained and their illustration form did not employ either 23
categories or 36 variables. Furthermore, if the extra variables were included as was
indicated on the results tables, there would have been more than 108 variables. Despite
repeated enquiries, none of these concerns have been addressed by the authors.
4 multiple-regression analyses were calculated, one for each group against the
total population. That for an analysis to have 108 variables was unsatisfactory because
of the sample size required was recognised by Cohen in the paper. The variables were
rotated by some unspecified procedure but it is a mystery why they used the variables
that appear in the resultant tables, which were supposed to compare between diagnostic
180
E.L. Neale (1994) The Children's DDS, Art Therapy , V.11(2):119-126.
118