Table of Contents

Expression Required for Calculated Objects

  • 2026-01-09
  • Morten Lønskov

Overview

This best practice rule identifies measures, calculated columns, and calculation items that lack a DAX expression. All calculated objects must have a valid, non-empty expression to function correctly and prevent errors during model deployment and query execution.

  • Category: Error Prevention

  • Severity: High (3)

Applies To

  • Measures
  • Calculated Columns
  • Calculation Items

Why This Matters

Calculated objects without expressions will cause critical failures:

  • Model validation errors: The model will fail validation when saved or deployed
  • Query failures: Attempts to use the object in queries will generate errors
  • Broken dependencies: Other measures or calculations referencing the object will fail
  • Deployment blockers: Power BI Service and Analysis Services will reject models with empty expressions
  • Unexpected behavior: The object may appear in field lists but produce no results

Empty expressions typically result from incomplete object creation, copy/paste operations, or programmatic model generation errors.

When This Rule Triggers

The rule triggers when any of the following objects have an empty or whitespace-only expression:

string.IsNullOrWhiteSpace(Expression)

This applies to:

  • Measures: Should contain a DAX aggregation or calculation
  • Calculated Columns: Should contain a row-context DAX expression
  • Calculation Items: Should contain a DAX expression modifying the base measure

How to Fix

Manual Fix

  1. In TOM Explorer, locate the measure, calculated column, or calculation item
  2. Double-click to open the DAX Editor
  3. Enter a valid DAX expression
  4. Validate the syntax and save

Common Causes

Cause 1: Incomplete Creation

Object was created intending to define it later but was forgotten.

Cause 2: Template-Based Creation

Scripts or templates created objects without expressions.

Cause 3: Failed Copy Operation

Copied an object but the expression didn't transfer.

Example

Before Fix

Measure: [Total Revenue]
  Expression: [empty]
  FormatString: $#,0.00

Error when queried: "The expression for measure '[Total Revenue]' is not valid."

After Fix

Measure: [Total Revenue]
  Expression: SUM('Sales'[Revenue])
  FormatString: $#,0.00

Result: Measure functions correctly and returns aggregated revenue.

Compatibility Level

This rule applies to models with compatibility level 1200 and higher.