# Departure from overall distribution

Departure from overall distribution is an effect size measurement for the distribution test. It measures the extent to which a conditional distribution does not match the marginal distribution of the target field.

A large effect size suggests that the conditional distribution is very different from the overall target distribution.

The following procedure describes how the effect size is calculated:

- Subtract 1 from the number of target categories.
- Multiply this result by the total count in the conditional group.
- Divide the chi-square value of the distribution test by this result.
- Take the square root.

Effect size (ES) | Interpretation |
---|---|

ES ≤ 0.2 | The result is weak. Although the result is statistically significant, the conditional distribution does not differ much from the overall target distribution. |

0.2 < ES ≤ 0.6 | The result is moderate. The conditional distribution differs a moderate amount from the overall target distribution. |

ES > 0.6 | The result is strong. The conditional distribution is very different from the overall target distribution. |