Cramér's V

Cramér’s V is an effect size measurement for the chi-square test of independence. It measures how strongly two categorical fields are associated.

The effect size is calculated in the following manner:

  1. Determine which field has the fewest number of categories.
  2. Subtract 1 from the number of categories in this field.
  3. Multiply the result by the total number of records.
  4. Divide the chi-square value by the previous result. The chi-square value is obtained from the chi-square test of independence
  5. Take the square root.
Table 1. Interpretation of effect size
Effect size (ES) Interpretation
ES ≤ 0.2 The result is weak. Although the result is statistically significant, the fields are only weakly associated.
0.2 < ES ≤ 0.6 The result is moderate. The fields are moderately associated.
ES > 0.6 The result is strong. The fields are strongly associated.