What Is Cardinality? Why Rows Disappear Into (other)

In plain English

A dimension with three values is low cardinality; one with fifty thousand unique values is high. Above certain limits, GA4 groups the excess into a row labelled (other).

Once data is in that row it cannot be recovered for the affected period. This is what happened when a report shows a large unexplained (other) line.

What to know

Count of unique values

Per dimension.

High cardinality aggregates

Into an (other) row.

Not recoverable

For the affected period.

Caused by unbounded values

Full URLs with parameters, timestamps, free text.

Why it matters

The usual culprits are URLs with query parameters and free-text parameters. Stripping parameters and bounding values before sending them prevents the whole problem.

Common mistakes

×Sending full URLs with query strings as dimension values.

×Free-text parameters with unlimited variety.

×Timestamps or IDs as dimension values.

×Ignoring an (other) row rather than fixing the cause.

FAQs

What is the (other) row?

Aggregated values that exceeded the cardinality limit.

How do I fix high cardinality?

Bound the values: strip query parameters, use categories rather than free text.

WRITTEN BY TARIQ SALLAM

Marketing Consultant. Entrepreneur. Content Creator.

I'm a marketing consultant, entrepreneur and content creator. I help businesses grow through practical marketing, websites, SEO, content and AI.

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