The appearance of "(not set)" stems from the absence of values for specific dimensions (which can vary). This can be confusing and complicate data analysis. But fear not, this issue is not insurmountable.
Key dimensions where "(not set)" may occur:
Source/medium
Campaign
Landing page
Page title
Content groups
Country
Browser
Language
Product name
Main reasons for "(not set)" occurrences and ways to resolve them:
1. Data processing time. The first step is patience. Give GA4 48 hours to process data after setup or changes.
2. Error in UTM tagging or its absence. Check the correctness of UTM tags. Google already recognizes many parameters, but syntax errors can lead to "(not set)".
3. Lack of session_start event. This could be due to the expiration of the previous session's wait time or server-side tracking usage. Check settings and, if necessary, increase session timeout.
4. Incorrect Measurement Protocol setup. Ensure that the session_id is correct and current, and when sending events with past dates, use the correct timestamp_micros.
5. Issues with special parameters and audiences. Use fewer audience triggers and carefully monitor the sending of special parameters.
Recommendations for resolution:
1. UTM tagging verification: Ensure you're using the correct UTM tagging for tracking traffic sources.
2. Session setup: Be diligent with session settings and increase timeout if necessary.
3. Measurement Protocol usage: Double-check the implementation of MP, especially concerning session_id and timestamp_micros.
4. Custom dimensions and audiences: Minimize the use of complex triggers and carefully monitor the sending of all necessary parameters.
"(not set)" in GA4 is not a sentence but an opportunity to check settings and optimize data collection. Most issues can be resolved independently by paying attention to analytics configuration details.
If you work with GA4 to BigQuery exports, be sure to check out my SQL cheat sheet.
