Development of a 'bipolar' R-index

A new 'bipolar' R-index analysis was proposed and evaluated. Eighteen judge s evaluated red color in eight wine samples by comparing each sample with t he control. Judges indicated whether the sample had 'more', the 'same', or 'less' red color than the control, and whether they were sure or unsure of their decision. Three computational methods were used to examine the result s: the 'traditional' R-index, the 'bipolar' R-index (R-more or R-less) and the 'weighted-bipolar' R-index. While all three methods provided consistent results, the 'bipolar' R-indices reflected bidirectional differences among the samples thus providing more information. A refinement to the computati on ('weighted-bipolar' R-index) was an approach for eliminating the bias as sociated with overestimation of the sample size and accordingly changed som e of the significance levels. Further research is currently underway to exp and the scope and application of this method.