Microsoft Power BI Cookbook

DAX variables for performance

• The primary benefit of DAX variables is improved readability. However, variables can also reduce the number of queries associated with a measure (and hence its execution duration) since variables are evaluated only once and can be reused multiple times in an expression.

Look for DAX measures with multiple branches of IF or SWITCH conditions that reference the same measure multiple times. For these measures, consider declaring a variable that simply references the existing measure (VAR MyVariable = [Sales Amount] RETURN) and then reference this variable in each logical condition, rather than the measure.