SKEWX.S OpenBI

How lopsided an expression's results over a table's rows are, taken as a sample: the sample skewness.

Skewness says which way the values lean: 0 for a symmetric spread, positive when a few large values make a long tail to the right (most order sizes, most prices), negative for a long tail to the left.

Group: Aggregation. OpenBI’s own: DAX has no function of this name.

Syntax

SKEWX.S ( <table>, <expression> )

Returns

Number. The sample skewness of the results; BLANK for fewer than three, or when they are all equal.

Remarks

• The sample skewness, the one Excel's SKEW gives: the population's skewness (SKEW.P) times √(n (n − 1)) ÷ (n − 2), for n values. The factor makes up for a small sample, and comes close to 1 as n grows.
• Rows where the expression is blank are left out; fewer than three results, or results that are all the same, give BLANK.

Compared with DAX

An OpenBI function: DAX has none like it, so a measure or query that uses it works in OpenBI only, not in Power BI or Analysis Services.

Excel's SKEW gives the same number for the same values.

Examples

Eight values as a sample and as all there is

EVALUATE
ROW (
    "Sample", SKEWX.S ( DATATABLE ( "Value", INTEGER, { { 2 }, { 4 }, { 4 }, { 4 }, { 5 }, { 5 }, { 7 }, { 9 } } ), [Value] ),
    "Population", SKEWX.P ( DATATABLE ( "Value", INTEGER, { { 2 }, { 4 }, { 4 }, { 4 }, { 5 }, { 5 }, { 7 }, { 9 } } ), [Value] )
)

Monthly liters of each product

Does a product sell steadily, or have a few big months?

EVALUATE
SUMMARIZECOLUMNS (
    Products[Product],
    "Skewness", SKEWX.S ( VALUES ( Sales[Month] ), [Liters sold] )
)
ORDER BY Products[Product]

A blank row is left out

EVALUATE
ROW (
    "With a blank", SKEWX.S ( DATATABLE ( "Value", INTEGER, { { 1 }, { 2 }, { BLANK () }, { 10 } } ), [Value] ),
    "Without", SKEWX.S ( DATATABLE ( "Value", INTEGER, { { 1 }, { 2 }, { 10 } } ), [Value] )
)

Related functions

SKEWX.P, SKEW.S, KURTX.S, STDEVX.S.

Last updated 8 November 2026 · OpenBI Studio 0.3.78