Hello @ljain and @tubitute ,
There was a bug in GA4 that attributed large numbers of session default channel grouping to "Unassigned". This issue has been resolved in June 2023. However, if it hasn't in your case, then here is how you can troubleshoot this. Let me know if this worked for you or not -
SHORTER VERSION -
1. Scope - Remember, that traffic acquisition reports are session-scoped, and user acquisition reports are user-scoped. So, expecting both of the reports to tally when it comes to purchase conversions, would be an incorrect expectation to set.
2. UTM Parameters - Whenever you are setting your campaigns, please be very careful of the UTM Parameters you insert. GA4 will assign anything that is not present in any of these sets as unassigned. Please go through these sets, and set your UTM Parameters accordingly - you are essentially assigning here, how you would like to attribute your conversions to multiple channels ( support.google.com/analytics/answer/9756891?hl=en )
LONGER VERSION -
We have to understand how user acquisition and traffic acquisition reports work in GA4. Lets deep dive -
1. User Acquisition Report: this is a user-scoped report that uses the "First User Default Channel" grouping - this means it aggregates together the all channels by which users first arrived at your site/app.
2. Traffic Acquisition Report: this is a session-scoped report that uses the "Session Default Channel" grouping - this means it aggregates the channels by which users arrived at your site/app every time they initiated new sessions
Now let's understand this practically -
Consider this scenario: You visit our website, easyinsights.ai/ directly for the first time. After exploring our content, you close your browser. The next day, while searching on Google for information on migrating from UA to GA4, you come across our article and access our website again to read it. Three days later, you encounter a search Ad on Google, prompting you to click and explore our website once more. Finally, two days later, while searching for more GA4 insights, you stumble upon another one of our articles and access our website again. This time, you decide to book a consultation with us regarding your GA4 issues and concerns.
A. Now this is how the User Acquisition Report will work -
1. Since you initially reached our website directly during your first visit, the Direct channel will be attributed as the source that brought you to our website.
2. Subsequently, any session you open after that will also be attributed to the Direct channel. This means that each session will be counted as 4 sessions.
3. Similarly, any conversions or events you perform from that point onward will be attributed to the Direct channel. It will record the conversion you made and any other events you might initiate during your subsequent sessions.
B. This is how the Traffic Acquisition Report will work -
1. In this example, each Channel group will have a session attributed to it. The sessions are calculated individually, resulting in organic Search having two sessions, while Paid Search and Direct each have one session.
2. Even if your first visit to our website was through the Direct channel, and you eventually performed a conversion, the session leading to the actual conversion was initiated when you reached our website through your last Google search, as highlighted in the example above. Therefore, the channel grouping responsible for the conversion, in this case, is not Direct but Organic Search.
Purchase Conversions Marked "Unassigned" in Traffic Acquisition Report - Now that you know the mechanism of attribution in both traffic and user reports, you understand the importance that the nomenclature for source/medium holds in GA4 ( Nomenclature is here - support.google.com/analytics/answer/9756891?hl=en) . If the UTM parameters you have assigned are not correct, then the reports will wrongly attribute the conversion, and the attribution will be unassigned if its anything other than the groupings given in the list above.
Therefore, when you are working on campaigns, be very careful as to how you assign the UTM parameters.