How to find your best marketing channel on Shopify

To find your best marketing channel on Shopify, decide the job first: new customers or repeat orders. Then score each channel on that job in GA4 and Shopify, put its cost beside it, and check it against your break-even. The leader usually earns the title only after a holdout test shows it adds sales.

Best is a job description, not a trophy. A channel can be the best opener and the worst closer in the same month. The steps below score channels on the job you need done, with menu paths from the GA4, Shopify and Google Ads help pages.

You need four things: GA4 with purchases marked as key events, your Shopify admin, each channel's spend and your gross margin.

Step by step

1. Name the job. Decide whether this quarter needs first-time customers or more repeat orders, and write it at the top of your sheet. It decides which column wins. Shopify's channel report can show new and returning customers for each channel. Path: Shopify admin > Growth > View channel report.
2. See who brings people the first time. GA4's User acquisition report files each user under the channel that first brought them. Sort it by new users, then by total revenue. Path: GA4 > Reports > Acquisition > User acquisition.
3. See who opens, assists and closes. The Key event attribution paths report splits each path into early, mid and late touchpoints. The early segment is the first 25% of touchpoints, and the late segment is the last 25%. Path: GA4 > Advertising > Key events dropdown > Key event attribution paths.
4. Compare first click with last non-direct click. In Shopify, open Performance by referring channel and pick models in its Attribution menu. A channel that gains under first click opens journeys; one that gains under last non-direct click closes them. Path: Shopify admin > Analytics > Reports > Category filter > Marketing > Performance by referring channel.
5. Put a cost on each new customer. Shopify's campaign report shows customer acquisition cost: spend divided by the first-time customers attributed to the campaign. Facebook and Google campaigns show no cost on the Growth page, so take their spend from Ads Manager and Google Ads. Path: Growth > View channel report > channel name > campaign name.
6. Set the floor. Break-even ROAS is 1 divided by your gross margin. Shopify works out gross margin per product once a cost per item is filled in. Path: Shopify admin > Analytics > Reports > Category filter > Profit Margin > Gross profit by product.
7. Test the leader before you crown it. Credit cannot tell you what a channel adds. Ask Google or Meta for a conversion lift study, or switch the channel off in some regions. Path: the Lift studies tab under Campaigns > Experiments in the Google Ads Campaigns menu; Experiments in Meta.

A worked example

Start with one store's export. In its Journeys sheet, journeys with 1 touch carry 79.5% of revenue. In a one-touch journey, first click and last click name the same channel. Journeys of two or more touches hold 20.6% of revenue in the same Journeys sheet. That is the only slice a model swap can move. If your export looks like that, steps 3 and 4 settle about a fifth of the money, and step 7 settles the rest.

Now a made-up month, in round numbers. For illustration, say a store sells through Meta, Google Shopping and email, at a 40% margin.

If you sort by last non-direct click, Google Shopping wins with €16,000, and email looks like a bargain. For illustration, email's claimed return is 28x: €14,000 of sales on €500. If you sort by first click, Meta wins: €24,000 of sales started there, and it brought 150 of the 240 first-time customers. If the job is new customers, Meta's €40 per new customer beats the others' €50.

Then the floor. The Break-even sheet in one store's export shows the sum: at a 40% margin, break-even ROAS is 2.5x, since 1 divided by 0.40 is 2.5. For illustration, Meta's last-click return is 2x, under that floor, while its first-click return is 4x. If you judged Meta on last click alone, you would cut the channel that brings most of your new customers. For illustration, Google Shopping sits in between: it closes more than it opens, at €50 per new customer. If your prices hold up in the comparison, that is a closer worth keeping. A test will say how much of its credit it earned.

For illustration, email's 10 first-time customers say it mostly sells to people who already know you, so it belongs to the repeat job. The growth leader is Meta, on credit. Step 7 decides whether it keeps the title. If a lift test finds it adds sales worth 2.5x its spend or more, it earns the next budget step.

What to check when the report looks wrong

• Direct tops the list. Shopify's last click and first click models both count direct visits. Switch to last non-direct click, which hands Direct the order only when the whole journey was direct. GA4's models already skip Direct unless every visit on the path was direct.
• GA4 has no first click model. Google retired the first click, linear, time decay and position-based models in November 2023. Use the User acquisition report's first user view instead.
• User and traffic reports disagree. They count different things: User acquisition is scoped to new users and Traffic acquisition to new sessions. Google says not to compare their metric values.
• Channel names differ between tools. Shopify sorts referrers into Direct, Search, Email, Social and Unknown. GA4 has a much longer list of default channels. Map them once, in a sheet, before you compare.
• A paid channel sits in Unassigned. GA4 uses Unassigned when no channel rule matches, which usually means a missing or odd UTM tag. Fix the tag, then wait for fresh data.
• Sessions and conversion rate jumped in late September. Shopify's session measurement rollout ran from 21 to 23 September 2026. Compare channels on sales and customers across those dates, not on sessions.

What to do this week

1. Price a new customer per paid channel. In Shopify, open the Growth page and select View channel report. Click a paid channel, then its biggest campaign. Read customer acquisition cost. Pass: you can write a cost per new customer next to each paid channel. Fail: the cost is blank, as Shopify warns for Facebook and Google, so divide their spend by first-time customers yourself.
2. List your first-touch channels. In GA4, select Reports, then Acquisition, then User acquisition, and sort the channels by total revenue. Pass: the top three differ from your last-click top three, so you have openers to protect. Fail: they are the same, so your journeys are short and a test will tell you more than any model.
3. Book a test for the leader. In the Google Ads Campaigns menu, go to Campaigns > Experiments and open the Lift studies tab. Start a Conversion Lift study there. Pass: the leading channel's campaigns show as eligible. Fail: they do not, so plan a geo holdout test by hand.

Check the homework. Your GA4 Attribution paths export already holds the evidence. Causality Engine reads that one file and shows what each channel caused next to what last-click gave it, in 1 to 2 minutes, for €99 once (excluding VAT), refundable within 30 days. Check the homework

Sources, 1 October 2026: User acquisition report (Analytics Help); Key events attribution paths report (Analytics Help); Marketing reports (Shopify Help Center); Measuring marketing performance (Shopify Help Center); Profit reports (Shopify Help Center); Set up Conversion Lift based on users (Google Ads Help); About Conversion Lift (Meta Business Help Center); Get started with attribution (Analytics Help); Key event attribution models report (Analytics Help); User acquisition report vs. Traffic acquisition report (Analytics Help); Default channel group (Analytics Help); Acquisition reports (Shopify Help Center).

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