E-commerce Integrity module (30 checks)

Duplicate purchase detection

Duplicate purchase events are the most common and costly e-commerce tracking error. They inflate reported revenue and conversion rates, making it impossible to trust GA4's revenue figures. The module analyses the ratio of unique transaction IDs to total purchase events. A ratio below 1.0 (i.e. the same transaction ID appearing multiple times) is flagged as a critical finding.

Common causes include the purchase confirmation page firing the event on every reload, or server-side and client-side tracking both sending the same event without deduplication logic.

Missing item parameters

The GA4 e-commerce schema requires specific item-level parameters: item_id, item_name, price, and quantity. Missing parameters cause blank rows in product reports and make it impossible to analyse performance at the item level. The module checks parameter coverage across purchase, add_to_cart, and view_item events.

Checkout funnel gap analysis

A healthy checkout funnel shows progressively smaller event counts from begin_checkout to add_payment_info to purchase. Anomalous ratios — such as more purchases than begin_checkout events, or a begin_checkout count far exceeding add_to_cart — indicate missing event instrumentation at one or more funnel steps. These gaps make funnel analysis unreliable.

Currency consistency

If transactions are reported in multiple currencies without consistent currency codes, GA4 cannot aggregate revenue accurately. The module checks whether multiple currency codes appear in purchase events and whether the property's currency setting matches the dominant currency in the data. Mixed currencies without proper handling is flagged as a high-severity finding.

Refund tracking

GA4 supports refund tracking via the refund event. The module checks whether refund events are present and, if your property processes a non-trivial volume of transactions, flags the absence of refund tracking as a medium-severity issue. Without refunds, reported revenue in GA4 will be higher than actual net revenue.