What is first click attribution?

First click attribution gives all the credit for a sale to the first channel the buyer interacted with. It usually answers who introduced the buyer, not who closed the sale. GA4 and Google Ads no longer offer it, but Shopify's marketing reports still do. If most of your buyers buy on their first visit, it changes little.

What one store's data shows

The usual answer sells first click as the fair deal for discovery. Last click flatters the channels that close, so first click is said to pay the ones that open. One store's export has a first-click column, so you can see who it actually pays.

One store's anonymised GA4 export, 1 January 2024 to 21 August 2026. It holds shares of revenue only: no ad spend, no order counts.

On the Channels sheet, the first-click column gives Direct 57.7% of revenue. As far as GA4 can tell, the biggest introducer in this store is a visit with no known source.

The channels first click is meant to champion score nothing. Paid Social and Organic Video both hold 0.0% on the Channels sheet, under first click as well as the other two views.

That does not mean they introduced nobody. A post someone scrolled past, or a video watched without a click, leaves no first touch to credit. First click can only pay for introductions that GA4 saw arrive with a source.

So where can first click change anything? Only on journeys with more than one touch, where the first visit and the last can be different channels.

On the Journeys sheet, journeys of 2 to 3 touches hold 12.2% of revenue and took 12.5 days to buy. Those journeys have few touches but many days between them, which is where an opener and a closer can part ways.

The export cannot say what any opener caused. It holds shares of revenue, not spend or orders, and a credit rule only divides sales that already happened.

Why does the usual answer mislead?

Because "first" only means first on record, and each tool keeps a different record.

• GA4 no longer offers it. Since November 2023, GA4's attribution reports run on data-driven attribution or one of two last-click models. Google Ads says the same four rules-based models are no longer supported.
• Hardly anyone used it. In April 2023, Google said less than 3% of Google Ads web conversions used those four models.
• Shopify's first click forgets. Shopify's help says the first interaction resets when a visitor buys nothing within 30 days of a session. After each order, the next referrer also becomes the first interaction for the next order.
• It counts direct visits. Shopify's First click includes direct visits. A buyer whose first recorded visit was typed in gives the whole sale to Direct, however they heard of you.
• Only clicks count, on one device. A friend's tip, a podcast mention or a social ad seen but not clicked never enters the record. GA4 also recognises users by browser or device, so the phone that found you and the laptop that paid can look like two people.

GA4 still keeps a first-touch view, just not as a model. Its User acquisition report sorts users by First user default channel group, the channel that first acquired them. That value stays fixed as users return, so their later sessions and revenue stay in the row of the channel that first brought them.

What can first click not tell you?

It cannot tell you whether the introduction mattered. Someone already hunting for a product like yours gives first click to whatever they happened to click first.

It cannot judge the closers. Email, retargeting and branded search earn nothing unless they also came first.

Nor does it tell you what to cut. Read it next to last click instead. A channel that is strong under first click and weak under last click opens journeys; the reverse closes them.

Both views describe credit, not cause. Only a holdout test shows what a channel adds, by switching it off for some buyers and keeping it on for others.

What to do this week

1. Run Shopify's first click next to last click. In Shopify admin, go to Analytics > Reports, filter the Category to Marketing and open Performance by referring channel. In the Attribution menu, select First click and Last click for the same dates. Pass: your top channels hold similar sales under both, so most buyers convert in one visit. Fail: a channel holds far more under first click, so it opens journeys that others close.
2. Open GA4's first-user view. Go to Reports > Acquisition > User acquisition and choose First user default channel group in the dimension picker. Read Total revenue, then the same column in Traffic acquisition. Pass: the same channels lead both. Fail: a channel leads in User acquisition but trails in Traffic acquisition, so it brings in buyers who come back through other doors.
3. Check how long your multi-touch buyers take. In GA4, open Advertising > Attribution > Attribution paths, set Path length to greater than 1 and read Days to key event. Pass: most paths finish inside a month, so Shopify's first click sees where they began. Fail: many run longer, so Shopify's reset cuts them short; read the opener in User acquisition instead.

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: Get started with attribution (Google); About attribution models (Google); First click, linear, time decay, and position-based attribution models are going away (Google); Marketing reports (Shopify); User acquisition report (Google); Scopes of traffic-source dimensions (Google); User acquisition report vs. Traffic acquisition report (Google); Key events attribution paths report (Google)

Related answers

• All Attribution models questions
• How to see first click attribution in Shopify and GA4
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• First click attribution, defined
• Causal attribution, explained