Table of Contents

Set SummarizeBy to None for Numeric Columns

  • 2026-01-09
  • Morten Lønskov

Overview

This best practice rule identifies visible numeric columns (Int64, Decimal, Double) that have a default aggregation behavior (SummarizeBy) other than None. Most numeric columns should not be automatically aggregated, as summing values like IDs, quantities in non-additive contexts, or codes produces meaningless results.

  • Category: Formatting

  • Severity: High (3)

Applies To

  • Data Columns
  • Calculated Columns
  • Calculated Table Columns

Why This Matters

Default aggregation on inappropriate columns causes serious issues:

  • Incorrect analysis: Users get meaningless totals (sum of CustomerIDs, etc.)
  • Misleading dashboards: Visualizations show wrong numbers by default
  • User confusion: Users must manually change aggregation for every visual
  • Wrong decisions: Business decisions based on incorrect automatic aggregations
  • Data credibility: Users lose trust in the model and data

Common columns that should NOT be aggregated include IDs, keys, codes, ratios, percentages, and non-additive quantities.

When This Rule Triggers

The rule triggers when a column meets ALL these conditions:

(DataType = "Int64" or DataType="Decimal" or DataType="Double")
and
SummarizeBy <> "None"
and not (IsHidden or Table.IsHidden)

In other words: visible numeric columns that have a summarization behavior other than "None".

How to Fix

Automatic Fix

This rule includes an automatic fix:

SummarizeBy = AggregateFunction.None

To apply:

  1. In the Best Practice Analyzer select flagged objects
  2. Click Apply Fix

Manual Fix

  1. In TOM Explorer, locate the column
  2. In Properties pane, find Summarize By
  3. Change from Sum, Average, Min, Max, Count, or DistinctCount to None
  4. Save changes

Common Causes

Cause 1: Default Import Behavior

Numeric columns default to Sum aggregation during import.

Cause 2: Lack of Column Review

Models deployed without reviewing column aggregation settings.

Cause 3: ID Columns Not Hidden

Numeric ID columns remain visible with default Sum aggregation.

Example

Before Fix

Column: CustomerID
  DataType: Int64
  SummarizeBy: Sum

Result: Visual shows "Sum of CustomerID: 12,456,789" (meaningless number)

After Fix

Column: CustomerID
  DataType: Int64
  SummarizeBy: None

Result: Visual requires explicit aggregation or shows individual Customer IDs

Compatibility Level

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

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