RATZ index

The Rip-Index ( R elativer A nstieg the T refferquote respect to the Z ufallstrefferquote ) is a characteristic parameter describing the quality of the screening methods in the medical or psychological area. The index was proposed for the first time in 1992 by H. Marx and indicates how much a test procedure performs better than a random assignment. The values usually vary between 0 (the screening is just as good as chance) to 1, with values from 0.3 being classified as a slight improvement in the prediction quality, values from 0.6 being classified as a clear improvement. Negative values mean that a completely random division produces better classification results than screening.

The Ratz index is calculated as follows: ${\ displaystyle {\ text {RATZ}} = {\ frac {{\ text {hit rate}} - {\ text {random hit rate}}} {{\ text {max. Hit rate}} - {\ text {Random hit rate}}}}}$

literature

P. Marx, W. Lenhard: Early prognosis of school competencies . Ed .: M. Hasselhorn, W. Schneider. Hogrefe, Göttingen 2010, Diagnostic Features of Screening Methods.
H. Marx: Methodical and substantive arguments for and against an early identification and prediction of reading and spelling difficulties. In: Diagnostica. 38 (3), 1992, pp. 249-268.

Web links

Test parameters - Further information on calculation and evaluation aids at psychometrica.de