Google Ads vs Google Analytics 4: Conversion Tracking Guide

For advertising executives, understanding conversion tracking is crucial. It allows you to measure the effectiveness of your campaigns, optimize your ad spend, and ultimately drive better results. Google Ads and Google Analytics 4 (GA4) both offer robust conversion tracking mechanisms, but they serve different purposes and have unique strengths. Google Ads tracks conversions that result directly from your ad campaigns, giving you a clear picture of your ROI. GA4, on the other hand, tracks user behavior across multiple touchpoints on your website or app, offering a more holistic view of user interactions.

Difference Between Google Ads vs Google Analytics 4 Conversion Tracking
The primary difference between Google Ads and GA4 lies in their attribution models and the scope of data they capture. Google Ads uses last-click attribution by default, attributing conversions to the last ad clicked before the conversion. This model can be adjusted to attribution models like first-click, linear, or time decay.

GA4 uses event-based tracking, allowing for more flexible and detailed data collection. It supports multiple attribution models, including data-driven attribution, which uses machine learning to determine how different touchpoints contribute to conversions.

Introduction to Attribution Models
Currently, both GA4 and Google Ads only offer Last Click and Data-Driven Attribution (DDA) models. If you’re using different models on both platforms, your conversion numbers will differ.

For instance, if a user sees your ad, visits the site, abandons it, and later comes back through organic search, the last-click attribution model will credit Organic Search. However, if the user returns directly, Paid Search will receive the credit.

Key Event Window – Also known as the lookback window, this determines how far back a touchpoint is credited for a conversion (renamed to key events in GA4). By default, it is 30 days in Google Ads and 30 days for acquisition key events (first_visit and first_open) in GA4, but 90 days for other key events. If you’re using different lookback windows, the numbers won’t match.

🚨Note: Conversions are renamed as Key Events in GA4 but will still be referred to as Conversions when shared/exported to Google Ads.

• Different Conversion Dates: Google Ads credits conversions based on the date the ad was clicked, whereas GA4 credits conversions based on the date the conversion occurred. If a user sees an ad on March 21st and fills out a form on March 25th, Google Ads will record it under March 21st, while GA4 will record it under March 25th. This difference in attribution dates can cause discrepancies.
• Processing Times: Conversions in Google Ads are reflected more quickly than in GA4, which can take 24-48 hours (sometimes even 72 hours) to process, leading to discrepancies until fully processed.
• Counting Method: Depending on whether you select to count every conversion or only one conversion within the same session, the data can vary significantly between platforms. For example, if you count every conversion in GA4 but only count once in Google Ads, the data will differ.
• Refunds: If you track refunds on one platform but not the other, the numbers will vary due to refunded transactions.
• Event Name Length: If the length of a GA4 event name exceeds 40 characters, Google won’t be able to append it with “_c” to mark it as a conversion, so it won’t be counted. However, Google Ads will still count it.
• Cross-device Tracking: While Google Ads allows for cross-device tracking, GA4 can only perform cross-device tracking if Google Signals are enabled.
• Conversions Not Tracked in GA4: Conversions from phone calls and view-through sources are available in Google Ads but not GA4. GA4 only tracks conversions that occur on the website/app, so these won’t be included.
• User Consent and Ad-Blockers: If a user doesn’t consent to being tracked on the website or uses ad-blocking extensions, GA4 won’t be able to place the tracking cookie and record user interactions or conversion events. Google Ads can bypass this issue as its tracking code is only fired when the conversion event occurs.
• Reporting Freshness: This differs from processing times and refers to how quickly conversion data is reflected in reports. Google Ads conversion numbers typically show up within 3 hours, while conversions imported from GA4 to Google Ads can take up to 9 hours. It’s not recommended to base decisions on very recent data.
• Conversion Exclusions: Google Ads can exclude conversion data if it detects malicious ad clicks, but GA4 will still display them. Additionally, if developers, CROs, etc., perform test conversions on the main website, they can inflate numbers in GA4 but not in Google Ads. Therefore, it’s recommended to have a test property to send any test data.

Why Use the Google Ads Conversion Tracking?
Using Google Ads conversion tracking is beneficial for marketers who need to measure the direct impact of their ad campaigns. It allows you to see which ads and keywords are driving conversions, helping you optimize your budget and improve your ad strategy. With Google Ads, you can track various conversion actions, such as website purchases, form submissions, and phone calls, giving you a comprehensive view of your campaign performance.

Why Use the Google Analytics 4 Conversion Method?
Google Analytics 4 provides a more detailed and nuanced view of user interactions across your site or app. It allows you to track a wide range of events and define custom conversions, giving you flexibility in how you measure success. GA4’s enhanced measurement capabilities, such as cross-platform tracking and predictive metrics, help you understand the full customer journey and make data-driven decisions to improve your marketing efforts.

Choosing Between Google Ads vs Google Analytics 4 Conversions
Choosing between Google Ads and GA4 conversions depends on your specific needs and goals. If your primary focus is on optimizing ad spend and measuring direct ad impact, Google Ads conversion tracking is the way to go. It provides clear insights into which ads drive conversions and allows for easy budget adjustments.

However, if you require a more comprehensive view of user behavior and want to understand how different touchpoints contribute to conversions, GA4 is the better choice. Its advanced tracking capabilities and flexible attribution models provide deeper insights into the customer journey, helping you make informed decisions to improve overall marketing performance.

Summary
Both Google Ads and Google Analytics 4 offer valuable conversion tracking tools, and the choice between them depends on your specific objectives and the level of detail you require in your data analysis. Consider your goals and choose the method that best aligns with your marketing strategy.

Image: @freepik
Source: Measure School