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Working in the marketing industry, you’ve probably seen reports many times where data from one source differed from that from another, and especially when you wanted to compare results from Universal Analytics, Google Analytics 4 and those from the Google Ads system. If so, this article is for you! Stay tuned until the end, and I’ll try to explain to you what they are and where the data differences between the above-mentioned marketing tools come from.
Differences-in-data-between-Google Ads, and Google Analytics
It might seem that since both tools come from Google, both of which collect data on user behavior and actions on a website, the results can’t be that different from each other. Meanwhile, they do. And it’s not always an implementation problem. There are several main reasons for the difference in reported data:
1. Source of data
Configuring conversions in the Google Ads Panel, we have the option of adding code to the page or importing data from Google Analytics. As you probably guessed – depending on which way you choose, you will see different data on your events in the reports. More often than not, you may find that the conversion data coming from Google Analytics will be less than that coming from Google Ads. From my experience, I can tell you that the biggest differences related to this, occur when we compare purchase conversions in Google Ads and transactions in Google Analytics. And this, in turn, is related to the next reason.
2. Attribution
Google Analytics Universal uses the attribution model “last indirect click”. This means that the transaction will be attributed to the source of the last indirect interaction before the purchase (i.e., a Facebook ad, for example). On the other hand, if purchase conversions in the Google Ads dashboard are measured using Google Tag Manager tags, they will be attributed to ad interactions.
This is also where the striking, decimal conversion number comes from – this is also due to the different attribution models that Google Ads uses. If a user enters a site from several sources (e.g., Google search, Facebook ads, Instagram, Youtube, etc.) and ultimately makes a conversion, then depending on the attribution model chosen, the conversion will be distributed among visits from different sources. The Google Ads system assigns different weights to different sources in driving conversions, resulting in decimal data. Google Analytics Universal, on the other hand, using the attribution model of the last non-direct click – will always show us the full number.
If you want to carefully analyze the differences in conversion rates depending on the chosen model, it is worth reviewing the attribution model comparison reports in Google Analytics. This will allow you to see how the number of conversions varies depending on the selected source and attribution model.
The attribution model comparison report in Google Analytics Universal can be found by clicking on the report “Conversions” → “Multichannel Paths” → “Comparison of Attribution Models“.
As “Type” include “All” and then select which comparison of “Last Non-Direct Click” and, for example, “Item Attribution“.
If, on the other hand, you want to find such a report in Google Analytics 4, just click on the “Advertising” section and in the options “Attribution” → “Model Comparison“. As the first one, select the model “Recent Click – Preferred in Google Ads” and compare it, for example, with the model “Data-based“, which is the default model of GA4.
3. Conversion attribution date
You already know that Google Analytics focuses on overall traffic, while Google Ads only focuses on those users who clicked on an ad. This is another reason for data discrepancies in your reports. Imagine that when looking for sports shoes for spring, you clicked on a Google Ads ad on March 15, but the transaction didn’t happen until 3 days later, so on March 18. How will this show up in your reports? Google Ads will record as a conversion the last ad click before the transaction (i.e. March 15), while Google Analytics will record the moment you made the purchase, so it will be March 18. This situation is also illustrated by the conversion forecast bar in the Google Ads dashboard, which often shows how many conversions arrive retroactively.
To better understand this – do a test! Write down on a given day how many conversions Google Ads is currently showing you, and compare that to the number of conversions 30 days later from the same time period. Many times, there will be more of these conversions.
4. Reporting
If you are in hot water and like to know everything at once, then unfortunately I have to worry you 🙂 The data in the reports, both in Google Ads and in Google Analytics, will never be visible at once (in Google Analytics you can only view actions on the site in real-time reports). In both accounts, information about user actions, will appear with a delay. In Google Ads, information, e.g. about views, clicks, conversions, may appear up to 3 hours after recording the event, while in Google Analytics the data may appear up to 24 hours (data related to improved e-commerce, may be visible in reports with a delay of up to 2-3 days).
Differences between number of clicks in Google Ads and sessions in Google Analytics
If you want to compare data between Google Ads and Google Analytics, remember that the former tool tracks ad clicks, while the latter – sessions. Why am I telling you about this? Because, for example, if a user clicks on an ad twice in one hour, Google Ads will record this as two clicks, in the course of one session. How, on the other hand, will Google Analytics perceive this? Quite the opposite. A visit to the site thanks to an ad will be counted as one click, but in two sessions.
Differences in data between Universal Analytics, and GA4
If you’re already a user of the latest Google Analytics 4 service (and if you’re not, you should do so as soon as possible!), you’ve probably compared reports from the old version of Analytics many times to those in GA4. Such a comparison can make a lot of fuss in your head, so it’s very important to be aware that these two tools are very different on many levels.
The most important change, in the context of this article, is the approach to measuring users and their behavior on the site. Universal Analytics was based on measuring sessions and page views, while GA4 measures events and their parameters, which are much more detailed. You also won’t find the rejection rate you’re familiar with in the latest Google Analytics 4, but the engagement rate has appeared. It’s also worth remembering that the old Universal Analytics reports data according to the aforementioned, attribution model based on the last, indirect click. In GA4, the default model is data-driven.
The difference also appears in the topic of user data collection. While in the old version of Analytics you could choose from several options (14, 26, 38, 50 months or “does not automatically expire”), in GA4 you have the choice of storing user data for only two time periods: 2 months or 14 months.
Important – remember, when creating a Google Analytics 4 account, to immediately change the data collection option in the administration panel and switch it from 2 months (default) to a longer period of time.
Despite the differences between Universal Analytics and GA4, is it worthwhile to measure data in both of these tools?
Of course! Tracking data from two Analytics accounts, or so-called dual tagging, can bring you a lot of benefits, including that you will have time to quietly get to know and learn how to use GA4 while collecting data in Universal Analytics in parallel. You will also be quicker to spot possible errors resulting from incorrect configuration of the latest version of GA4. Comparing data in both tools and drawing business conclusions from it is not the best idea, but when you see that in Universal Analytics you have 3,000 new users in a given period of time, and in GA4 only 100 users, it will signal to you that something is wrong. And it’s better to have the possibility of such verification than not to have it, right? 🙂
How is data collection affected by privacy policy?
The topic of collecting user data in accordance with privacy policies has been as much of a hot topic lately as the implementation of GA4 In order to properly collect data, you need to properly implement Consent Mode, or consent acquisition mode, on your site. This will allow us to measure users’ traffic and actions even if they do not consent to cookies, according to the RODO. Google using Consent Mode data modeling can restore up to 70% of lost information! If you are interested in this topic, I refer you to the specifications: https://developers.google.com/tag-platform/devguides/consent#gtag.js
Are differences in conversions a cause for concern?
If you are sure (and have checked!) that all tracking codes are implemented correctly at your site, there is no reason to worry. Variations in the data in the reports are due to the peculiarities of advertising and analytics tools and specific settings (such as the attribution model). However, remember to always keep a watchful eye on the data, catch anomalies, and if you need to consult your results, contact digital agency and discuss the issue with specialists.
Wondering if the difference in your data is ok?
Above all, our specialists will help you understand and use these differences to optimize your ads and analyze user behavior. Contact us and let’s talk about your campaigns!
If you want to learn more about the practical workings of GA4, we ran a webinar on the subject! You can find it on our YouTube channel.
