The Three-Model Truth: How GA4 hides last-click, first-click and data-driven in plain sight

Why Do GA4 Reports Feel Like Solving a Puzzle?

You've hit on the exact reason GA4 feels like solving a puzzle with pieces from three different sets.

Marketers have spent over two years wrestling with GA4's fundamentally different approach to attribution since Universal Analytics shut down in July 2023, according to Google's own migration timeline. Most assume they're fighting a broken system.

They're not.

GA4 isn't broken. It's running three different attribution models simultaneously, and attribution is tied to the scope of the dimension (the row in your table), not the report itself.

In my experience working with UK businesses over the past 20 years, this is the number one source of GA4 confusion. When clients show me their Traffic Acquisition report for the first time, they're always looking at what I call a "Frankenstein" of attribution models. From what I've seen auditing dozens of GA4 accounts, this multi-model approach catches every business owner off guard initially.

What Are GA4's Three Attribution Models?

GA4 runs session-scope, user-scope, and event-scope attribution models side by side. Every GA4 account I audit has this same setup running whether the business owner knows it or not.

The honest answer is that most businesses I work with have no idea this is happening behind the scenes.

Dimension Scope	Attribution Model	What It Measures	Example
Sessions	Last-Click (Non-Direct)*	Which channel started this specific session	User clicks Facebook ad, browses, leaves. Session = Facebook
Users	First-Click	Which channel first brought this user	User clicks Facebook ad, returns via Google search. User = Facebook
Key Events/Revenue	Data-Driven Attribution (DDA)	AI-determined credit across the journey	Facebook gets 60% credit, Google gets 40% = fractional numbers

*This is a simplified explanation of GA4's session attribution logic, which can be more nuanced in practice.

Here's what matters: you're not choosing between models. You're seeing all three at once.

Once clients understand this three-model system, everything else clicks into place. What I tell every client is this: the "confusion" becomes clarity once you know what each column represents.

How Does the Traffic Acquisition Report Actually Work?

Your Traffic Acquisition report shows three different attribution models in one view. When I walk clients through their first GA4 audit, this is always the lightbulb moment.

Each column in your report is answering a fundamentally different question. The Traffic Acquisition report combines session attribution, user attribution, and event attribution into a single interface that initially appears contradictory.

Here's what happens when you open your Traffic Acquisition report and look at a single row for "Paid Search":

Sessions and Users Columns Show Different Attribution Models

These columns show Last-Click (Non-Direct) attribution for sessions and First-Click for users. Google Analytics 4 is saying: "This specific session was started by Paid Search" or "This user was first acquired through Paid Search."

In my client work, I've seen businesses spend months trying to "fix" discrepancies between these columns, not realising they're measuring completely different things. The session column tracks immediate traffic source behaviour, while the user column tracks acquisition behaviour over the entire customer lifetime.

Key Events and Revenue Columns Use Data-Driven Attribution

These columns show Data-Driven Attribution. Google Analytics 4 is saying: "Based on our machine learning algorithms, Paid Search deserves £450.50 of credit for the total journey, even if it wasn't the last click for every single sale."

Data-Driven Attribution uses Google's machine learning to assign conversion credit based on how each touchpoint statistically contributes to conversions. This creates a fundamentally different measurement approach compared to rule-based attribution models.

The Key Mismatch Between Attribution Models

You're comparing two different mathematical worlds in the same row:

• Source of the visit: Last-Click
• Value of the visit: Data-Driven Attribution

If you have high Direct traffic in the Sessions column but high Revenue in the Email row, people are clicking your emails (Data-Driven Attribution giving credit), but returning via bookmark to finish the purchase (Session Last-Click).

The mismatch between attribution models is where most business owners think GA4 is "broken." It's not broken-it's just showing you three different stories about the same customer journey. I've walked hundreds of clients through this exact realisation over my career, and the pattern is always the same: initial confusion followed by strategic clarity.

Why Am I Seeing 0.45 Conversions?

Data-driven attribution creates fractional conversion numbers because it splits credit. This catches every business owner off guard the first time they see it.

You can't have "0.45" of a physical conversion.

These decimal numbers exist because the Data-Driven model decided that "Email" only deserved 45% of the credit for that specific sale. The other 55% went to different touchpoints in the customer journey.

GA4's shift from session-based to event-based tracking means GA4 can split credit across multiple channels. Your old Universal Analytics would have given 100% credit to one channel. Google Analytics 4's machine learning algorithms distribute credit based on what they calculate each touchpoint contributed to the final conversion.

What I tell every client is this: those fractional numbers aren't errors-they're insights. They show you which channels are working together to drive conversions, not just which one happened to get the last click.

Can I Change My GA4 Attribution Model?

You can partially control GA4's attribution by changing your Key Events model. I've tested this across multiple client accounts and here's what actually works.

The short answer is yes, but only for part of your data.

While User and Session scopes are locked into First-Click and Last-Click respectively, you can change what model your Key Events use. This gives you control over revenue attribution while maintaining the multi-model architecture for traffic analysis.

Navigate to Attribution Settings

Google Analytics 4 attribution settings are located at Admin > Data Settings > Attribution Settings.

Check Your Reporting Attribution Model

In my experience auditing GA4 setups, most accounts default to Data-Driven Attribution, but if someone changed it to Last Click, your whole row would finally "match" across all columns. However, you lose the cross-channel journey insights that Data-Driven Attribution provides.

Understand Your GA4 Attribution Options

GA4 now offers Data-Driven Attribution (default) plus two last-click variants. Rule-based models like linear and time-decay are no longer selectable, according to Google's current attribution documentation.

The available options are:

• Data-Driven Attribution (machine learning based)
• Last Click (gives 100% credit to final non-direct click)
• Last Click (gives 100% credit to final click including direct)

Make Your Attribution Choice

Some old-school marketers prefer Last Click for simplicity. But you lose the cross-channel journey insights that help you optimise your marketing mix. Businesses that stick with Data-Driven Attribution make better budget allocation decisions.

I've seen clients switch to Last-Click for "simplicity," only to switch back six months later when they realise they're missing crucial insights about how their channels work together. The initial learning curve pays dividends in marketing effectiveness.

How Do I Use GA4 Attribution for Better Business Decisions?

Understanding GA4's three-model system connects directly to the "Know What is Working" stage of your growth flywheel. Here's what I tell every client during their first GA4 strategy session:

The key insight is this: the "confusion" becomes clarity once you know what each column represents. Most businesses I work with spend months fighting the system instead of leveraging its multi-dimensional insights.

Stop Comparing Different Attribution Models

Your sessions data and conversion data use different models. Accept this or change your Key Events to Last-Click if you want consistency.

From my client work, the businesses that fight this system waste months. The ones that embrace it start making better decisions immediately. The multi-model approach reveals customer behaviour patterns that single-model attribution masks.

Use the Attribution Mismatch Strategically

If Email shows low sessions but high revenue attribution, you know it's an assist channel. Double down on email nurturing.

This mismatch reveals your marketing funnel's true structure. Channels with high Data-Driven Attribution scores but low Last-Click sessions are typically your best nurturing and influence channels.

Track Your Actual Customer Journeys

The fractional conversions show how customers really move through your funnel. Most touch multiple channels before buying.

In my experience, businesses with longer sales cycles see the most dramatic differences between Last-Click and Data-Driven Attribution. The longer your customer journey, the more valuable these multi-touch insights become.

Optimise Based on Contribution, Not Just Last Touch

Data-driven attribution reveals which channels deserve more budget, even if they don't get the final click.

The confusion isn't a bug. It's three different answers to three different questions, all displayed in one report. Once you know what you're looking at, you can actually "Get Better" by making decisions based on real customer behaviour, not just the last thing they clicked.

Businesses that embrace this multi-model approach rather than fighting it see measurably better returns on their marketing spend. In my experience, clients who master this concept typically see meaningful improvements in their marketing efficiency within six months.