Google Analytics 4 Audiences: GA4 Predictive Audiences for Ads

Old Google Analytics (UA) was about "What happened." Google Analytics 4 (GA4) is about "What will happen." The biggest upgrade in GA4 isn't the event model; it's the Predictive Audiences engine. GA4 uses machine learning to assign a "Probability Score" to every user. You can create an audience of "Users with >90% probability to buy in the next 7 days" and sync it to Google Ads. This is arguably the most powerful retargeting signal available today.

In this guide, we break down the Predictive Matrix, the "Churn Prevention" plays, and how to set up the data link.

The Financial Logic of Predictive Audiences

Retargeting is usually inefficient because you retarget everyone.

• Segment A: Browsed for 10 seconds. 0% intent.
• Segment B: Added to cart, read reviews, visited pricing page. 80% intent.
• The Cost: If you bid the same for both, you essentially tax your high-intent budget to subsidize low-intent waste.

The Prediction Value: By focusing budget only on the top 20% of users (by probability), you can often cut CPA by 50% while maintaining 80% of the conversion volume.

Theory: How GA4 Predicts

GA4 needs data to "Unlock" these features.

• Requirement: At least 1,000 returning users in the last 28 days who converted.
• Requirement: Modeled data turned on. Once unlocked, GA4 looks at:
• Recency
• Frequency
• Session Duration
• Specific Events (e.g., scrolled 90%, clicked "Specs")

It combines these into a Propensity Score.

Framework: The 3 Predictive Buckets

1. Likely to Purchase (7 Days):
   • Strategy: High Bid. Aggressive Retargeting.
   • Creative: "Don't miss out. Stock is low." (Urgency).
2. Likely to Churn (7 Days):
   • Definition: Active users who are about to stop using your app/site.
   • Strategy: Win-Back.
   • Creative: "Here is a 20% discount." (Incentive).
3. Predicted Top Spenders (28 Days):
   • Definition: Users likely to have high LTV.
   • Strategy: VIP Treatment.
   • Creative: "Join our Loyalty Program."

Execution: Creating the Audience

1. Go to: GA4 → Admin → Audiences.
2. Click: "New Audience" → "Predictive" (Tab).
3. Select: "Likely 7-day purchasers."
4. Refine: You can adjust the "percentile."
   • Conservative: Target top 10% (Highest intent).
   • Aggressive: Target top 30% (More reach).
5. Sync: Ensure your Google Ads account is linked. The audience will appear in Google Ads Audience Manager within 24 hours.

Advanced Strategy: The "Predictive Exclusion"

This is a secret weapon for broad campaigns. When running a Broad Match or Display/YouTube campaign for new customer acquisition, you want to exclude current customers. But you should also exclude "Likely Purchasers." Why? Because if GA4 thinks they are going to buy anyway (Organic/Email), why pay for an ad click?

• Tactic: Exclude "Likely 7-day purchasers" from your Brand Search campaign.
• Result: You stop cannibalizing free conversions.

Case Study: The E-commerce Exclusion

Client: Fashion Retailer Problem: High Brand CPC, low incremental ROAS. Hypothesis: We are paying for people who are already in the checkout flow.

The Test:

1. Control Group: Standard "All Visitors" exclusion.
2. Test Group: Excluded "Likely 7-day purchasers" (Predictive).
3. Result:
   • Ad Spend dropped 15%.
   • Total Revenue remained flat (meaning those users bought anyway via Email/Direct).
   • Net Profit: +$4,000/month (Saved ad spend).

Pitfalls to Avoid

1. The "Data Eligibility" Wait

You cannot use this on Day 1. GA4 needs history. If the "Predictive" tab is grayed out, you don't have enough conversions. Fix: Use standard behavioral audiences (e.g., "Add to Cart > 2 times") as a proxy until you hit the 1,000 conversion threshold.

2. Over-bidding on "Likely Purchasers"

These users are expensive. Everyone wants them. If you set your bid too high, you might burn margin. Rule: Monitor the CPA. If the CPA → Gross Margin, you are over-paying for easy wins.

3. Not Refreshing the Link

Sometimes the API link between GA4 and Ads breaks. Check Tools → Data Manager → Connected Products. Ensure the status is "Active."

Summary

Predictive Audiences are the "Minority Report" of marketing. You are stopping crimes (wasted spend) before they happen.

Your GA4 Checklist:

1. Check if you meet the 1,000 conversion threshold.
2. Create the "Likely 7-day purchaser" audience.
3. Test it as an "Observation" layer in your Search Campaigns.
4. Test it as a "Targeting" layer in your Display Remarketing.

Stop looking back. Start predicting.