Question from Reddit user:
Hi, I have a few campaigns running on Google Ads and have noticed that not all my conversions are being registered in the account. The conversion tracking is correctly set up and users are redirected to a thank you page following purchase. If I have 4 purchases for a product, perhaps 2 of them will come up under conversions in Google Ads and 2 will be missed.
I’m concerned this is going to affect the info my smart bidding campaigns receive to optimise for the future and affects my recommended CPA, as Google thinks I’ve had less conversions.
Any idea why this happens? Do I have to set up enhanced conversion tracking to avoid this? Is there anything else I can do?
Answer from Nabil:
The short answer is:
The issue where Google Ads misses a significant portion of your conversions, despite the tracking being set up on a thank you page, is almost always due to client-side tracking failures.
The Google Ads conversion tag is a piece of JavaScript that can be blocked or fail to execute in the user’s browser due to slow page load times, ad blockers, network interruptions, or privacy settings, especially if the user leaves the thank you page too quickly.
This directly starves your Smart Bidding campaigns of vital conversion data.
Yes, you absolutely should implement Enhanced Conversions to address this, and the most robust solution is to combine it with a server-side tracking environment.
The long answer is:
Your concern about Smart Bidding and recommended CPA is entirely valid, as machine learning models rely on complete, accurate conversion data to optimize performance; if Google only sees two of your four conversions, it will undervalue your campaigns.
The fundamental cause of this conversion loss is the reliance on the user’s browser (client-side) to fire the tracking tag on the thank you page.
When a user completes a purchase and is redirected, the browser is responsible for loading the page and executing the Google Ads tracking script via GTM.
If the user’s internet is slow, an ad blocker is active, or they hit the back button before the script finishes loading, the conversion data is simply never sent to Google Ads.
To fix this and recover your lost conversions, the most modern and reliable solution is to implement a server-side tracking infrastructure using the Google Ads API and a server-side container hosted on a platform like Stape or Google Cloud Platform.
The workflow for this is two-fold:
First, you capture the user’s Google Click ID (gclid) from the landing page and pass it to your server along with the purchase details.
Second, instead of relying on the client’s browser, your server-side environment is configured to use the Google Ads API to directly transmit the conversion data to Google Ads.
This process is essentially implementing Enhanced Conversions in the most resilient way: a server-side implementation.
Because the conversion is reported directly from your server to Google’s server, it completely bypasses the browser’s vulnerabilities, ensuring nearly all conversions are recorded.
By using GTM’s client-side container to capture the initial user identifiers and passing them to your server container, which then uses the Google Ads API to send the final purchase event, you guarantee that your Smart Bidding receives the comprehensive, accurate data it needs to lower your CPA and maximize your return on ad spend.
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