Quick Answer: Use native Google Ads conversion actions as your primary conversion, and import GA4 conversions as secondary. Importing GA4 as your primary means you're missing enhanced conversions, view-through conversions, and sending a weaker bidding signal to smart bidding. The extra setup is worth it.
Why This Question Comes Up
When you link Google Ads to GA4, Google walks you through an import. It feels like the clean move: one source of truth, fewer tags to manage, everything flowing through GA4. A lot of advertisers stop there and use imported GA4 conversions as their primary conversion action.
The dashboard looks normal. The campaigns run. You'd have no idea anything was off.
But you're leaving signal on the table, and smart bidding is running on a thinner diet than it should be.
What You Actually Lose With GA4 as Primary
Enhanced Conversions Don't Work
Enhanced conversions let you send hashed first-party data (email addresses, phone numbers) back to Google alongside the conversion. Google uses that data to match conversions to signed-in users, which improves attribution accuracy and feeds the algorithm better signal, especially as third-party cookies become less reliable.
The problem: enhanced conversions are not supported when your primary conversion action is an imported GA4 goal. The feature only works with native Google Ads conversion tags. If you're running imported GA4 conversions as primary, enhanced conversions aren't doing anything for you, even if you technically have them set up.
View-Through Conversions Are Missing
View-through conversions track users who saw your display or video ad but didn't click, then converted later through another channel. Native Google Ads conversion actions capture these. GA4 imported conversions don't.
For most lead gen accounts running display or video alongside search, that's a blind spot in your attribution data.
The Bidding Signal Is Weaker
Data-driven attribution, smart bidding, tCPA: all of these optimize based on the conversion data Google has. Native Google Ads conversion actions give Google the most complete picture: click-through, view-through, enhanced conversion matching. Imported GA4 conversions only hand over post-click, last-touch data by default.
You're asking the algorithm to optimize with one hand tied behind its back.
The Right Setup: Native as Primary, GA4 as Secondary
Here's how to fix it without starting from scratch.
Step 1: Create a Native Google Ads Conversion Action
Go to Goals > Conversions > Summary > New Conversion Action in Google Ads. Set up your conversion action. For lead gen, this is typically a form submission or thank-you page visit. Install the tag via GTM or gtag.js.
Set this as a primary conversion action. This is what smart bidding will optimize toward.
Step 2: Keep Your GA4 Import and Set It to Secondary
Don't delete the GA4 imported conversion. Keep it, but change its status to secondary conversion action. Secondary conversions show up in reporting but don't influence bidding.
This gives you a cross-reference point for reporting without letting GA4's limited signal override your native tag.
Step 3: Layer In Enhanced Conversions
Once you have a native Google Ads tag running, you can turn on enhanced conversions. In Google Ads, go to Goals > Conversions > Settings > Enhanced Conversions for Leads. You'll need to confirm that your form passes first-party data (hashed email or phone) to the thank-you page, and that your tag is configured to capture it.
This step alone can meaningfully improve your match rate, which feeds better data to data-driven attribution and smart bidding.
Does GA4 Still Matter?
Yes. Keep GA4 connected and use it for:
- Cross-channel reporting and assisted conversions
- Audience building
- On-site behavior analysis
GA4 is a reporting and analytics tool. Google Ads is an optimization engine. They serve different purposes, and feeding your optimization engine with native conversion data is what gets you better results from smart bidding.
If You're Managing Offline Conversions Too
If your business closes leads over the phone or in a CRM pipeline after the form submit, native Google Ads conversion actions are also the right foundation for offline conversion tracking. You'll need the GCLID captured at the form-fill point, which requires your native tag (or a server-side setup), not an imported GA4 goal.
If offline conversions are part of your setup, the OCT Setup Checklist walks through the full workflow. It's free at freak.marketing/oct-checklist.
FAQ
If I switch from GA4 imported to a native tag, will it reset my smart bidding learning period?
Yes, changing your primary conversion action can trigger a learning period as smart bidding recalibrates to the new signal. The tradeoff is worth it. You're moving from a weaker signal to a stronger one. If you're concerned about disruption, make the switch during a lower-volume period and monitor performance for 2-3 weeks.
Can I use both GA4 and native Google Ads tags without double-counting conversions?
Yes, as long as you set the native Google Ads tag as primary and the GA4 import as secondary. Secondary conversions are visible in reporting but don't count toward your primary conversion column or influence bidding. No double-counting.
What if my GA4 data and Google Ads data show different conversion numbers?
This is common and usually comes down to attribution model differences. GA4 defaults to last-click; Google Ads can use data-driven attribution. Custom UTM parameters can also break the link between GA4 sessions and Google Ads click data. Setting up native Google Ads tags and keeping GA4 as secondary reporting typically reduces the confusion.
Does this apply to ecommerce too, or just lead gen?
Both, but the enhanced conversions setup differs. For ecommerce, you'd use enhanced conversions for web (passing transaction data) rather than enhanced conversions for leads (passing contact data). The principle is the same: native Google Ads conversion action as primary, GA4 as secondary.