Question from Reddit:
Hey everyone,
I’ve been running search campaigns in a specific niche where phone calls are our primary conversion metric.
To track these conversions, I’ve been using two different systems: CallRail in one account and Google Ads conversions in another.
Here’s the breakdown of what I track:
- Calls from the website
- Calls from ads
- Form submissions
Primary Conversion Focus: Phone Calls
In theory, CallRail should outperform Google Ads in terms of tracking more conversions.
This is because CallRail is supposed to document more conversions than Google Ads, which should improve the algorithm’s performance, especially when using smart bidding methods such as Target CPA (TCPA) or Return on Ad Spend (ROAS).
However, I’ve encountered a surprising issue: the cost per conversion tracked by CallRail is significantly worse than what I get from Google Ads.
Has anyone else experienced similar issues? What do you think might be the issue here?
Any advice or suggestions would be greatly appreciated!
Answer from Nabil:
The short answer is:
Your surprising finding that CallRail’s cost per conversion is significantly worse than Google Ads is a classic symptom of a fundamental difference in how each system attributes a call conversion to a click, combined with potential data leakage or over-counting in CallRail.
CallRail may be tracking more total calls, but if a high percentage of those calls are being attributed to non-Google Ads sources or unidentifiable clicks, the total conversion volume you are sending to Google Ads for bidding optimization is actually lower or less accurate than what the native Google Ads tracking is capturing.
The solution is to use a server-side setup involving the Google Ads API and the CallRail API to precisely match the call to the original Google Click ID (gclid) before sending it to Google Ads, thus ensuring only high-quality, accurately attributed, first-party conversions are used for Smart Bidding.
The long answer is:
It is a common misconception that simply having a higher volume of conversion data automatically translates to a better cost per conversion (CPA) when using Smart Bidding strategies like Target CPA or Target ROAS.
The performance of these algorithms hinges entirely on the accuracy of attribution.
Your issue likely stems from one of two possibilities: either CallRail is over-counting non-valuable calls, or, more likely, it is failing to attribute a significant portion of its total conversions back to the Google Ads click.
The native Google Ads tracking is specifically designed to work within the Google ecosystem, using the gclid to create a seamless, high-confidence link between the ad click and the resulting call conversion.
CallRail, as a third-party system, relies on its own tracking numbers and session data to capture the gclid on your website, which can be vulnerable to interference from ad blockers, page speed issues, or cross-domain tracking problems, leading to data loss where the call is recorded, but the $gclid$ required for Google Ads attribution is missing.
This means your Google Ads account, while receiving more conversions in total from CallRail than from its native tracking, is receiving fewer correctly attributed, high-confidence conversions for optimization, causing the algorithm to struggle and your CPA to rise.
To fix this attribution gap, the most reliable approach is a server-side solution utilizing the Google Ads API, the CallRail API, and a platform like Stape or Google Cloud Platform.
This process works by treating CallRail’s record as the definitive source for the call event: first, you use the CallRail API to extract the full details of every call that meets your conversion criteria, including the unique tracking number and the visitor’s original landing URL, which often contains the $gclid$.
Second, you use the Google Ads API to upload these conversions directly to Google Ads.
By performing this match server-side, you bypass the unreliable client-side browser environment, ensuring that only conversions with a valid, verified gclid are passed to Google Ads.
This method guarantees that Google’s Smart Bidding algorithm is fed the highest quality, most accurately attributed first-party data, combining CallRail’s superior call capture with the robust attribution matching required for optimal performance, thus lowering your true cost per conversion.
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