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

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Measuring accuracy<br />

Altman's recommendation to plot the differences against the average score, for continuous<br />

measures, seemed clear and appropriate. Tables 1-15a (appendix 2) show rater's scores,<br />

discrepancy levels, the mean score for each subject and differences to that <strong>of</strong> the author.<br />

Plots <strong>of</strong> the distribution <strong>of</strong> the raters' scores (Figs 1-15 appendix 2) show concordance<br />

with the mean rating; for clarity the same minimum and maximum limits are used<br />

throughout. It must be remembered that the principal rating (R7 by the author) is not the<br />

true value, which is unknown, and for this purpose, the average <strong>of</strong> the mean trainee rating<br />

and that <strong>of</strong> the author 274 , acts as the best estimate for the unknown true value. A<br />

summary <strong>of</strong> these scores, the standard differences are tabulated below (table 16).<br />

Table 16: Standard deviation <strong>of</strong> the differences between the mean <strong>of</strong> the 6 trainee raters<br />

and the author ratings over 7 paintings<br />

S.Diff<br />

Variable Mean Std Dev Min Max<br />

RED -.02 1.35 -1.50 2.67<br />

YELLOW 1.12 1.21 .00 3.00<br />

ORANGE -.24 .42 -1.00 .00<br />

PURPLE -1.26 2.09 -5.33 1.00<br />

GREEN -.86 1.20 -3.00 .17<br />

BLUE -1.36 1.23 -3.00 .00<br />

BROWN -1.07 2.51 -5.83 2.17<br />

WHITE -.24 .63 -1.67 .00<br />

BLACK -.07 .69 -1.17 1.00<br />

INTENSITY 1.02 1.54 -.89 3.83<br />

PAINT LINE 1.21 1.26 -.33 2.72<br />

DRAW LINE -.06 .11 -.28 .00<br />

SPACE -.65 .68 -1.77 .00<br />

EM-TONE .17 2.01 -2.17 3.11<br />

FORM -.31 .68 -1.33 .67<br />

221<br />

95% limit <strong>of</strong> agreement;<br />

(expected differences by scale points);<br />

and likely direction <strong>of</strong> discrepancy<br />

-2.68 to 2.70 (

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