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About this lesson
Creating measures is all very well, but you need to understand why they return what they do. In this module we will explain how to identify the filter context applicable to your data point, and how that influences the way measures are calculated.
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Understanding Measure Calculation
Understanding how the DAX engine calculates measure results.
When to use
When you need to clarify why a value is being returned as it is, or when you need to debug a result.
Key concepts around measure calculation:
- Every measure result is evaluated independently
- Each measure starts with the raw and unfiltered data tables
- Filters are applied to the underlying tables based on the “Filter Context”, reducing the number of rows to use in the calculation
- The Measure’s arithmetic signature is applied to whatever rows are left
What contributes to Filter Context?
- The intersection of any fields used in the current visual (each data point is a cross section that inherits the rows/columns/axis/legend, etc.)
- Any selected data points in other visuals
- Selections made in any (all) slicers
- Page or report level filter selections
Hints & tips
- If the measure contains a CALCULATE() function, this debugging chart will not be sufficient for your needs. Please see the module on Understanding CALCULATE().
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