Affiliation dimension
Affiliation is the ecommerce dimension that labels the store, marketplace, or partner an order is attributed to, set via the affiliation parameter on the purchase event (and optionally per item). It lets one GA4 property separate revenue across multiple storefronts or fulfilment partners without standing up separate properties. It is a free-text label, so consistency is entirely on the sender.
What this means
GA4's affiliation parameter records which store or partner an order belongs to. Set on the purchase event — and available at item level too — it lets a single property report revenue broken out by storefront, channel partner, or fulfilment source.
It is the lightweight alternative to splitting commerce across multiple properties.
Consistency is on you
Affiliation is free text with no controlled vocabulary, so 'Main Store', 'main-store', and 'MainStore' become three distinct values and fragment your reporting. Define a fixed label per storefront and apply it identically everywhere the purchase event fires.
A short, agreed list of labels documented for engineers prevents the drift that otherwise accumulates.
- Labels the store or partner for an order
- Available at order and item scope
- Free text — enforce a fixed label set
How it appears in analytics and logs
An affiliation value names the store or partner for an order. Fragmented affiliations (varied spellings) mean the label is being sent inconsistently across the codebase.
Diagnostic use case
Use affiliation to split revenue across storefronts or partners within a single property when you send a consistent label on each order.
What WebmasterID can help detect
WebmasterID can tag purchase events with a storefront or partner label first-party, so multi-store revenue separates cleanly without third-party tracking.
Common mistakes
- Sending inconsistent spellings that fragment the report.
- Using affiliation for data that belongs in another dimension.
- Leaving affiliation blank in a genuinely multi-store setup.
Privacy and accuracy notes
Affiliation names a store or partner, not a person. WebmasterID treats it as first-party commercial context, never as a visitor identifier.
Related pages
- Transaction ID dimension
Transaction ID is the dimension that holds the unique identifier you assign to a completed purchase via the purchase event's transaction_id parameter. GA4 uses it to deduplicate purchases: two purchase events sharing one transaction_id within a window are treated as the same order, not two. Supplying a stable, genuinely unique value is what keeps revenue from being double-counted when a confirmation page reloads.
- Item list dimension
The item list dimension identifies the list context in which a product appeared — a search results page, a category grid, a recommendation rail. GA4 reads item_list_id and item_list_name from view_item_list and select_item events. This page explains list context and why consistent list naming makes it analyzable.
- The purchase event and e-commerce
The purchase event records a completed transaction and anchors all e-commerce reporting: revenue, items, and conversion value. It carries a transaction id, a value and currency, and an items array describing what was bought. The discipline is to record the order, not the customer — product and revenue data belong in the event, personal identity does not.
- Multi-site analytics
Separate revenue by storefront first-party.
Sources and verification notes
- GA4 developer docs — Measure ecommerce (purchase parameters)Documents the affiliation parameter at order and item scope.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.