GapFill Help

Reading the report

The missing purchases report compares your Shopify orders with the purchases in GA4 and shows which orders GA4 doesn’t have. It is free, and it is brought up to date whenever you open Home.

What it compares

Period

The last 30 days, leaving out the most recent 2 days. GA4 can take about a day to process a purchase, and GapFill doesn’t count an order as missing while GA4 may still be working on it.

How orders are matched

An order counts as tracked when GA4 has a purchase with the same transaction ID. GapFill works out from your real GA4 data whether your tag sends the order number or the order ID.

Orders left out

Test orders, cancelled orders, Point of Sale orders and draft orders are not counted.

The two bars

Shopify orders are on the left. On the right is what happened to those orders in GA4. Both bars are the same height, and the colours on the right show the split.

Tracked by your GA4 tag

Purchases your store’s tag tracked on its own.

Sent by GapFill (“To be sent” during the dry run)

Purchases the tag missed and GapFill sent to GA4. During the dry run, before you approve, nothing has been sent yet, so the label reads “To be sent”.

Still missing

Orders missing from GA4 that GapFill hasn’t sent: channels you have turned off in Settings, buyers who declined analytics cookies, and orders still waiting their turn.

Below the bars, the chart by day shows the same split for each day. If red or grey suddenly grows from one day on, something probably changed in your tag or theme that day.

The three breakdowns

Orders missing from GA4 are split three ways, to help you see where the gaps come from.

By channel

Where the order was created. Orders placed through your online store checkout are tag misses. In-app checkouts in AI assistants and social apps, and subscription renewals, never reach the tag at all. The badge next to each channel shows whether GapFill is set to send it.

You can change which channels are sent under What to send.

By source / medium

Online store orders grouped by the source and medium of the buyer’s last visit. GA4 has no source for a purchase it didn’t track, so this uses the source Shopify recorded (UTM parameters first, then Google click IDs, then the referrer).

When purchases from ads are missed, ad results look smaller in GA4 and Google Ads than they really were. This table shows which traffic is under-reported. It can differ from GA4’s own attribution.

By payment method

Missing purchases for each payment method. If one method has a much higher rate than the others, the cause is in that payment flow.

The usual case is a payment that sends the buyer to an external page. If they close the tab after paying instead of returning to the order status page, the tag never runs.

Cancellations and refunds by source / medium

The last table shows, for purchases GA4 did track, how many were cancelled or refunded for each source / medium. It helps you spot traffic that brings revenue but also many refunds. It is separate from the missing purchases.

If it says it couldn’t analyze your data

Sometimes the report is replaced by “Couldn’t analyze your data”. The causes and fixes are under Troubleshooting.