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

Reliability Analysis
Judgement of characteristics differentiating patient groups
All rating scales have limitations, especially those involving human subjects. Given
enough different people performing a measurement, individual differences will contribute
to error, but a single rater may be inconsistent, or may be scoring on other criteria than
the published instrument. If a measure is unreliable, there is no possible way that any
sort of statistically significant relationship or difference with that measure can be
documented. It makes little sense therefore to list the characteristics for every study in
the controlled and case analyses unless they have established inter-rater reliability so that
it is certain their scoring is consistent and their definitions of terms unambiguous.
Terms used in this analysis of studies
Most studies have some counted or presence/absence scales, but there is a wide range of
opinion on what is described as objective or formal qualities. Here, formal qualities are
broadly differentiated from objective qualities as relating to the structure of the picture;
how it is made, rather than why it is made or what it represents 173 . Objective decisions
can be made about elements of form and content; although a characteristic can be both
formal and objective, it cannot be formal and subjective. For this review, objective
categories may be considered as observable dimensions; for example: the presence or
absence of some element, countable items, differentiation of structural aspects or
elements of the picture, such as lines, shapes and colours. Objective dimensions also
173 This form description is broader than the formal description for the DAPA, which appears in Chapter
3. It is clearly not reasonable to apply criteria to studies which are not aimed at that point.
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