Spearman’s and Kendall’s Coefficients of Rank Correlation

The items in a sample or population can sometimes be ranked even though they cannot be measured on any objective scale. This is true, for instance, when people express preferences or opinions. Brighton may be considered more attractive as a holiday resort than Bognor, but less attractive than Bournemouth. Blackpool may be held to be even more attractive than Bournemouth. Although the resorts can be ranked according to their degree of attractiveness, there is no objective way of measuring the precise degree of attractiveness of the resorts. Attractiveness is not a variable that can be assessed using an instrument such as a ruler or a stopwatch, nor can it be counted.