Study first
Review the ideas behind the questions
Review when GA4 360 property architecture should split data and when it should aggregate it. Focus on source eligibility, data ownership, user access, event flow, custom definitions, start dates, and linked advertising accounts.
Choose split or aggregate architecture
Subproperties and roll-up properties solve different enterprise problems. A subproperty narrows a source property for a team or use case; a roll-up property combines multiple source properties for a broader view.
- Use a GA4 subproperty when a 360 source property needs filtered data or separate access governance.
- Use a GA4 roll-up property when leadership needs one view across multiple source properties.
- Standard GA4 properties are not eligible source properties for subproperties.
In Practice
Subproperties are for governed subsets
A regional or line-of-business team may need a filtered dataset and separate access. That is a subproperty use case, not just a custom report navigation problem.
Roll-ups are for broad views
A parent company with several brand properties can use a roll-up property for a holistic view while the brands keep their own properties.
Common mistakes
Using a roll-up property when the real need is a filtered regional subset from one source property.
Use a subproperty for the filtered regional dataset when the source property is eligible.
Q&A
Can a GA4 subproperty be created from a standard property?
No. The source property for a subproperty must be an eligible Analytics 360 property.
Can a roll-up property include another roll-up property as a source?
No. A roll-up property can include ordinary properties and subproperties, but not another roll-up property.
Respect event, access, and activation boundaries
A 360 property structure can change who sees data and where activation happens. It does not make every setting, event, or user permission flow automatically between related properties.
- A GA4 subproperty or roll-up property cannot create its own collected events through a new data stream.
- GA4 roll-up users must be configured separately from source-property users.
- Avoid linking both a GA4 source property and its subproperty to Google Ads for the same key-event export unless the duplicate-counting risk is deliberately handled.
In Practice
Events must exist upstream
A roll-up or subproperty can report and activate from eligible source data, but the underlying collected event must first exist in the source property path.
Roll-up history starts when the source is added
A roll-up property should not be promised historical source data from before the source was added to that roll-up.
Common mistakes
Expecting source-property custom dimensions to appear automatically in a roll-up property.
Plan to recreate needed custom dimensions and metrics in the roll-up property.
Q&A
Does adding a user to a source property give them roll-up access?
No. Add and configure users directly on the roll-up property.
Can a roll-up property import offline events directly?
No. Roll-up events must first exist in source properties, so direct offline event import into the roll-up is not supported.
Plan activation from the property that owns the decision
Enterprise GA4 architecture affects Ads links, key events, audiences, and costs. The property used for activation should match the team, data subset, and duplicate-counting risk.
- Google Ads links can be created at the GA4 property level for a source property, subproperty, or roll-up property.
- Linking both a GA4 source property and its subproperty to Google Ads can create double-counting risk.
- Events sent to a subproperty or roll-up property are processed again and can add 360 cost.
In Practice
Ads links need a single source of truth
Before importing key events, decide whether Ads should use the source property or the subproperty. Importing the same key event from both can make performance look inflated.
Architecture has a billing shape
Subproperties and roll-ups can solve governance problems, but every routed event is processed again. Cost review belongs in the architecture decision.
Common mistakes
Linking every related GA4 property to the same Ads account because more links feel safer.
Choose the property that matches the activation decision and avoid duplicate source-property and subproperty key-event exports by default.
Q&A
Why does Ads-link planning matter more with subproperties?
The same business action can be visible in related properties. Linking both a source property and its subproperty can create double counting, so the linked property should match the Ads decision.