Metrics of Association for Categorical Variables

Compare categorical associations using risk differences, risk ratios, odds ratios, signed phi, Cramér V and directional Goodman–Kruskal lambda. Work through transparent numerical examples and diagnose reference coding, zero cells, case-control sampling and prediction-error limitations. Prerequisites: two-way frequencies, proportions and square roots. Formulas are supplied for less familiar measures; significance testing is deferred. Includes single-select and multiselect practice with worked explanations and misconception-specific feedback.

Further reading and method references:

• SciPy: relative risk
• SciPy: odds ratios
• SciPy: categorical association
• Minitab: Goodman–Kruskal measures