The RCI as a measure of monotonic dependence

In this paper a statistical interpretation of a recent measure, called “Rankbased Concordance Index” (RCI), in terms of monotonic dependence relationship between a non-negative dependent variable and a quantitative independent one is provided. Due to its rank-based construction, the measure presents properties and features that make it suitable also in an ordinal context of analysis. In applied research many data sets contain observations from ordinal variables rather than continuous ones. In such situations, the study of dependence relationship among variables represents an interesting issue, since ordinal variables are not specified according to a metric scale. The proposal discussed here can thus contribute to solve this problem.