Diego Caro

Diego Caro

Data & CRO Consultant

Differences in conversion tracking systems: GMP vs GA

2 February 2022
4 mins

Have you ever reported on conversion tracker by Floodlight, Google Ads conversion tracking and Google Analytics and the total from these different systems did not match? We will explain the important components you should pay attention to when it comes to conversion tracking systems and the difference between the way these three systems measure conversions.

Analysing and visualising the interaction between your website or app users and your marketing tactics before they convert is essential to gather insights and choose the best decision to optimise the conversion rate.

Digital advertising has given us the possibility to reach people with timely and relevant messages, measuring conversions allows us to understand how effective these ads are from awareness to conversion. Previously we would rely on cookies to successfully measure our campaign, these cookies would bring us information about the interaction after a user clicked on an ad. However, since browsers have restricted the use of cookies, scenarios where it’s no longer possible to observe these conversions are increasing. 

The Digital Landscape is becoming complex with more and more gaps in media measurement, the most effective solution is conversion modelling. That means that machine learning will be used to quantify the impact of marketing efforts when the conversion cannot be tracked, so we will depend more and more on IA to make business decisions.

When measuring conversions, these are the initial key points you must consider :

  1. Make sure that you are measuring apples with apples, confirm that Floodlight, Google Ads, and Google Analytics columns are the same events. Sounds basic but believe me, it happens. 
  2. Confirm that your advertiser’s web server or redirection service hasn’t removed the gclid and gclsrc parameters from the landing page URL.
    When auto-tagging is enabled in Google Ads or your Google Analytics Account is linked with Search Ads 360, these parameters are automatically added. If the parameters are removed, the attribution of the visits to your search campaign will not be possible to measure and the metrics in GA and SA360 will definitely not match.  
  3. Some metrics are supposed to get different results since the conversion systems have differences in terms of measurement. Differences include how the conversion attribute system counts, the lookback window, the time zone and more.

Common measurement differences

Multi-Channel Funnels in Google Analytics are not included since conversions’ attribution is different from the GA reports detailed below.

Time Zone

Systems may use different time zones to attribute conversions.

  • Floodlight: The time zone of the Campaign Manager account
  • Google Ads: The time zone of the engine account
  • Google Analytics: The time zone of Google Analytics view. 


Attribution’s day (Exact moment of Attribution/ Attribution window?)

The attribution’s day is when a conversion is reported to have occurred. Let’s see how each system reports the same conversion.

  • Floodlight reports it as the day of conversion
  • Google Ads reports it as the day of the click on the Ad
  • Google Analytics reports it as the day of the conversion


Lookback Window

The lookback window is defined as the period of time between a customer ad’s clicks and a conversion, such as a purchase, lead generation, and more. The Conversion-tracking systems could have different Lookback windows.

  • Floodlight: Can be customised  
  • Google Ads: Can be customised between 7 and 90 days 
  • Google Analytics: Can be customised, but the default is six months. For GA data in Search Ads, the used Lookback Window is the one set in GA.

Last-click attribution 

  • When a search ad is clicked and later a display ad is clicked before a conversion.
    • Floodlight: The conversion credit goes to Display click if the data is on a display ad manager by Google Marketing Platform.   
    • Google Ads: The conversion credit goes to Search click if the data is on a display ad manager by Google Marketing Platform or another system. 
    • Google Analytics: The conversion credit goes to display ads if the data is on a display ad manager by Google Marketing Platform or another system.
  • When a search ad is clicked and later an organic search result is clicked before a conversion.
    • Floodlight: The conversion credit goes to the ad in Search Ads 360 
    • Google Ads: The conversion credit goes to the ad in Search Ads 360 
    • Google Analytics: The conversion credit doesn’t go to the ad in Search Ads 360.

All conversions and unique conversions

Some systems count just one conversion per user, while others count every conversion that occurs after a click.

  • Floodlight: The way that Campaign Manager counts can be configured
  • Google Ads: Use flexible conversion counting
  • Google Analytics: Google Analytics Goals counting can be configured 

Scaled conversion metrics

The conversion sometimes cannot be measured directly, because of data regulations and data factors such as the unavailability of cookies when conversions can’t be measured directly. 

  • Floodlight: The conversion metrics will be scaled by Search Ads 360
  • Google Ads: scales conversion metrics
  • Google Analytics: does not scale any conversion metric 

Ad robots and other spam

The way that some systems deal with the spam from robots is different

  • Floodlight: Visits from ad robots are excluded
  • Google Ads: Clicks from ad robots are excluded and provide a more advanced spam filter
  • Google Analytics: visits from ad robots are not excluded.

As you can see, there is a chance that we don’t get the exact same data results in every single platform for our marketing efforts. However, we can minimise the gaps by setting up our platforms correctly. If you have any questions regarding Conversion tracking systems, send us an email at info@makingscience.com.