Cross-channel attribution: how credit gets double counted
Every platform reports the orders it can tie to its own ads inside its own window, so the same order shows up in several dashboards. Reconcile one full week of platform claims against Shopify orders and the any click model.
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By Joris van Huët, Founder & CEOPublished 4 min read
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Each ad platform counts the orders it can tie to its own ads inside its own window, so one order can appear in several dashboards. Shopify's documentation says its any click model "allocates more credit than orders you've received" and offers it for reconciling what each channel reports. For illustration: a store has 100 orders in a week, Meta reports 60 purchases, Google Ads 55 and TikTok 20, which is 135 claimed for 100 orders, so at least 35 claims are repeats.
Why do platform totals add up to more than your orders?
A platform's window is measured from its own ad interactions. Google Ads describes a conversion window as the period after an ad interaction, such as a click or video view, during which a conversion is recorded in Google Ads, and its default click-through window is 30 days. TikTok's 2022 announcement of Attribution Manager says pixel and Events API advertisers default to 7-day click and 1-day view. The windows differ, each platform grades its own homework against its own ads, and an order that followed clicks on two platforms falls inside both windows.
Systems that assign each order once behave differently. GA4 distributes credit across touchpoints, and Google says the fractional credit sums to 1.0 in the key events column. Shopify's last click and last non-direct click give the order to one channel. Only its any click model gives each clicked channel full credit, and Shopify says that model is best used to analyse a single marketing channel and can also reconcile the attribution each channel reports. This page cites no public measurement of how often platform claims overlap, so the reconciliation below is how you measure it for your own store.
How do you reconcile platform claims with Shopify orders in one week?
- Pick the week. A full week that ended at least a week ago, so click windows have closed.
- Align the reports. In each platform, use the same window, click only where it allows, and the store's time zone.
- Add the claims. Total the purchases the platforms report for that week.
- Count the orders. Take Shopify orders for the same dates and, in Shopify's marketing reports, the orders credited to each channel under the any click model.
Pass: the platform total is at or below Shopify's orders, and each platform is at or below Shopify's any click count for its channel. Fail: the total is above your orders, which proves overlap by arithmetic, or a platform is above Shopify's count for its channel, which means it credits orders Shopify has no recorded click for. A ratio at or below one does not prove there is no overlap, because platforms also miss orders they can't match. If a platform is higher, rerun its report for that week with views switched off where the platform allows, and compare again.
Keep the ratio and budget on total revenue over total ad spend, not on the sum of platform ROAS figures.
Does deduplicated credit show what caused the sale?
No. Deduplication answers who gets the order, and whether the credited channel caused it is a separate question that needs a test. Gordon and colleagues compared observational methods with randomised experiments in 15 US advertising experiments at Facebook and report that the observational methods often fail to produce the same effects (Marketing Science, 2019). When a tool is sold as cross-channel attribution, ask how it assigns each order once, whether its total equals your orders, and whether any of its numbers were checked against an experiment.
Sources, 30 September 2026: Shopify marketing reports (Shopify Help Center); About conversion windows (Google Ads Help); Select attribution settings (Google, Analytics Help); Fuel your TikTok campaign measurement with flexible attribution windows (TikTok for Business, 2022); A Comparison of Approaches to Advertising Measurement (Gordon, Zettelmeyer, Bhargava and Chapsky, Marketing Science, 2019, peer-reviewed).
Related answers
Frequently asked questions
Why do Meta, Google and TikTok report more sales than Shopify?
Each platform counts the orders it can tie to its own ad interactions inside its own window, so one order can be counted by several platforms. Shopify records the order once. Reconcile one full week to see how much overlaps.Which attribution model adds up to my real orders?
Models that assign each order once: GA4 distributes fractional credit that sums to 1.0 per key event, and Shopify's last click and last non-direct click give the order to one channel. Shopify's any click model gives each clicked channel full credit, so it adds up to more than your orders.Can I compare channels on ad platform ROAS?
Only with care. Each platform's ROAS rests on its own window and its own claimed orders, so the numbers overlap. Compare channels on your total revenue over total ad spend, and check any platform's ROAS with a holdout.
Go deeper: Incrementality testing, explained.
Sixty-second versions of these ideas: Causality Engine on YouTube Shorts.
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Terms in this article
- AttributionAttribution identifies user actions that contribute to a desired outcome and assigns value to each. It reveals which marketing touchpoints drive conversions.
- Attribution DiscrepancyAttribution Discrepancy is the variance in conversion data reported between different marketing analytics platforms. It arises because platforms use different models to assign credit.
- Attribution WindowAttribution Window is the defined period after a user interacts with a marketing touchpoint, during which a conversion can be credited to that ad. It sets the timeframe for assigning conversion credit.
- ConversionConversion is a specific, desired action a user takes in response to a marketing message, such as a purchase or a sign-up.
- DashboardsDashboards are graphical user interfaces that provide at-a-glance views of key performance indicators (KPIs). They monitor campaign performance and visualize attribution insights.
- ExperimentsExperiments are scientific procedures that test hypotheses or demonstrate facts. In marketing, experiments like A/B tests determine the causal effect of campaign changes, enabling data-driven decisions.
- Google AdsGoogle Ads is an online advertising platform where advertisers bid to display ads, service offerings, and product listings.
- MER vs ROASMER (marketing efficiency ratio) is total revenue divided by total ad spend; ROAS is revenue credited to a specific channel divided by that channel's spend. MER cannot be gamed by attribution but is blind to channels; ROAS is channel-level but only as honest as the attribution behind it.