analytics-dictionary / term / tracking & measurement

Custom dimension

A custom dimension is an extra attribute you register in your analytics tool so it can be used in reports.

Written by Reflective Data experts · updated Oct 5, 2026

In GA4, event parameters and user properties only appear in standard reports after you register them as custom dimensions. Examples are content category, logged-in status or plan type.

Registered dimensions count toward limits, so choose the ones that answer real questions.

Custom metric Event parameter User property

// how we can help

Need tracking you can trust? We implement and audit analytics across GA4, Adobe, Mixpanel and more. Analytics & tracking services → · Audits

Marketing mix modeling (MMM)

Marketing mix modeling uses statistics on aggregated data to estimate how each channel contributes to sales.

data-thresholding.md

Data thresholding

Data thresholding hides some report data to protect user privacy, usually when numbers are very small.

retention-rate.md

Retention rate

Retention rate is the percentage of users who come back or stay active over a given…

heatmap.md

Heatmap

A heatmap is a visual overlay that shows where users click, move and scroll on a…

ga4-explorations.md

GA4 Explorations

Explorations are GA4 free-form analysis tools for building custom reports such as funnels, paths and segment…

impression.md

Impression

An impression is each time an ad, a listing or a piece of content is displayed…

← full analytics dictionary