Which type of correlation involves ranking data rather than using absolute values?

The correct answer involves the concept of ranking data to determine the relationship between variables. Rank-order correlation specifically focuses on the ranks of the data points rather than their actual values. This means that rather than considering the raw numerical scores, rank-order correlation looks at the order of those scores.

Spearman's Correlation is also a method that ranks data, and it is synonymous with rank-order correlation, but it makes specific calculations of the degree of the relationship using these ranks. Kendall's Tau similarly utilizes rank data but operates on a different statistical basis to assess the strength of association. In contrast, Pearson's Correlation works with raw score data and assumes that the data follows a normal distribution, making it unsuitable for rank-oriented analysis.

Therefore, ranking is central to the idea of rank-order correlation, making it the proper choice for this question regarding correlation that emphasizes ranking over absolute values.