theilsU

The theilsU function calculates the Theil's U uncertainty coefficient, a value that measures the association between two columns in a table. Its values range from 0.0 (no association) to 1.0 (perfect agreement).

Syntax

theilsU(column1, column2)

Arguments

column1 and column2 are the columns to be compared

Returned value

a value between 0 and 1

Return type is always Float64.

Example

The following two columns being compared below have a small association with each other, so the value of theilsU is small and positive:

SELECT
    theilsU(a, b)
FROM
    (
        SELECT
            number % 10 AS a,
            number % 4 AS b
        FROM
            numbers(150)
    );

Result:

┌────────theilsU(a, b)─┐
│  0.30195720557678846 │
└──────────────────────┘