Somers’ D: Mastering Ordinal Data Analysis
Somers’ D: Asymmetric Measure of Association The Core Definition of Somers’ D Somers’ D is a fundamental statistical tool in psychology and social sciences, defined precisely as an asymmetric measure of association between two variables that are measured on an ordinal scale. Unlike symmetric measures which treat both variables equally, Somers’ D explicitly distinguishes between […]
Kendall’s Tau: Mastering Correlation in Psychological Data
Introduction to Kendall’s Tau Kendall’s Tau, often simply denoted as Tau ($tau$), is a fundamental non-parametric statistic employed extensively within the fields of psychology, statistics, and social sciences. It serves as a robust measure of the association, or dependence, between two measured variables, specifically designed for use when those variables are measured on an ordinal […]
Polychoric Correlation: Measuring Hidden Latent Traits
Introduction and Definition of Polychoric Correlation The concept of polychoric correlation stands as a specialized and crucial statistical measure within psychometrics and multivariate analysis, designed specifically to quantify the association between two variables that are observed and measured on an ordinal scale. Unlike the ubiquitous Pearson product-moment correlation coefficient, which assumes underlying continuous and normally […]