Google Analytics 4 has completely replaced Universal Analytics, but I still see businesses that either haven’t set up GA4 properly or have lost critically important data due to configuration errors. Worst of all is when a business owner is looking at reports, making decisions based on them, and the data turns out to be inaccurate.
Over the past year, we’ve audited GA4 for dozens of clients. In 80% of cases, we found significant setup issues. This article will help you avoid common mistakes and set up analytics correctly.
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What Changed in GA4 Compared to Universal Analytics
GA4 is not just an updated version of the previous analytics. It’s a fundamentally different system with a different logic of operation.
Key Differences
Event-based model instead of session-based – this is a fundamental change in data collection approach. In GA4, everything is an event: page view, click, scroll, conversion. This gives much more flexibility in analysis because you can track any user interaction with the site. Unlike Universal Analytics, where the session was the central unit of measurement, the focus now shifts to individual user actions.
Key Events instead of Goals – this is not just a name change. Google renamed Conversions to Key Events for better integration with Google Ads, where “conversions” have a different meaning. Functionally, the logic remains similar, but it’s important to remember the limit of 30 key events per property. This means you need to carefully choose which actions are truly critical for your business.
Predictive analytics – this is one of the most interesting features of GA4, which uses machine learning to predict user behavior. The system can predict the likelihood of conversion and the likelihood of customer churn, allowing you to proactively work with your audience instead of reacting to facts.
Cross-platform tracking solves the long-standing problem of data fragmentation. Now you can track a single user profile through Web and App in one property. Thanks to User-ID, the system combines sessions of one user from different devices and platforms, providing a real picture of the customer journey.
Types of Events in GA4
GA4 distinguishes four categories of events, and understanding this classification is critically important for correct setup.
Automatically collected events are collected automatically without any additional settings. These include page_view, first_visit, session_start, as well as scroll, click, and file_download. These events provide a basic picture of user behavior on the site immediately after installing the GA4 code.
Enhanced measurement events expand automatic collection with additional data. These include outbound clicks (transitions to external sites), site search (search on the site), video engagement (interaction with video), and file downloads. These events can be turned on or off in the data stream settings depending on your business needs.
Recommended events are events that Google recommends using for different types of businesses. For e-commerce, these are purchase, add_to_cart, begin_checkout. For SaaS – sign_up, login, share. For lead generation – generate_lead, view_item. Using recommended names allows GA4 to automatically build corresponding reports and integrate with Google Ads.
Custom events are events that you create yourself for the unique needs of your business. They require technical implementation through Google Tag Manager or code on the site. Use custom events to track specific actions not covered by standard events.
Step-by-Step GA4 Setup
Step 1: Creating a Property and Data Stream
Start by going to GA4 Admin and creating a new property. This is the basic entity that will contain all your data. Next, set up a data stream – this can be Web for websites, iOS or Android for mobile apps, or a combination for omnichannel businesses. After creating a data stream, you will receive a Measurement ID in the format G-XXXXXXXX – this is a unique identifier used for data collection.
Step 2: Installing Tracking Code
There are three main ways to install GA4, each with its own advantages.
Google Tag Manager – this is the recommended method for most businesses. GTM provides maximum flexibility in settings, easy event management without developer intervention, and versioning of all changes. You can quickly add new events, test them in preview mode, and roll back changes if needed.
Direct integration through gtag.js is suitable for sites where page load speed is important and there’s no need for complex settings. This method has fewer dependencies, but managing events requires working with the site code.
CMS plugins for WordPress, Shopify, and other platforms provide the fastest setup, but have limited functionality. This method is suitable for simple sites without complex tracking requirements.
Step 3: Setting Up Enhanced Measurement
- Page views (by default)
- Scrolls (90% depth)
- Outbound clicks
- Site search
- Video engagement
- File downloads
Step 4: Setting Up Key Events
Determine critically important actions for the business:
- purchase (purchase)
- add_to_cart (adding to cart)
- begin_checkout (checkout start)
- add_payment_info (adding payment)
- generate_lead (form submission)
- phone_click (click on phone)
- schedule_appointment (booking a consultation)
- download_pdf (downloading materials)
- sign_up (registration)
- start_trial (trial start)
- subscription_purchase (subscription)
- feature_used (feature usage)
Step 5: Setting Up E-commerce (if needed)
For online stores, set up enhanced e-commerce:
- view_item (product view)
- add_to_cart (adding to cart)
- remove_from_cart (removing from cart)
- begin_checkout (checkout start)
- add_shipping_info (shipping information)
- add_payment_info (payment information)
- purchase (purchase)
Step 6: Setting Up Custom Dimensions
- user_type (new/returning)
- customer_segment (B2B/B2C)
- traffic_source_custom
- content_category
Common GA4 Setup Mistakes
Mistake 1: Missing Key Events
- Identify key actions for the business
- Set up the corresponding events
- Mark them as key events in Admin
Mistake 2: Event Duplication
- Check DebugView in real time
- Ensure the tag triggers only once
- Use trigger conditions in GTM
Mistake 3: Incorrect Data Retention
- Admin → Data Settings → Data Retention
- Change to 14 months
- Do this immediately after creating the property
Mistake 4: Lack of Cross-Domain Tracking
- Admin → Data Streams → Configure tag settings
- Set up domains for cross-domain measurement
- Test transitions between domains
Mistake 5: Internal Traffic in Data
Cause: Internal traffic is not excluded
- Admin → Data Streams → Configure tag settings
- Define internal traffic with office IP addresses
- Create a filter to exclude
Mistake 6: Lack of User-ID
- Set up User-ID transmission upon authorization
- Admin → Data Streams → User-ID
- This is especially important for SaaS and e-commerce
Mistake 7: Incorrect Event Parameters
- Check the transmission of all necessary parameters
- For e-commerce: value, currency, items
- For lead gen: form_name, lead_source
Checking the Correctness of Setup
DebugView
- Install the Google Analytics Debugger extension
- Go to the site and perform actions
- Check in GA4 → Admin → DebugView
- Confirm that all events trigger
Realtime Reports
- Reports → Realtime
- Perform test actions on the site
- Confirm that data appears
- Check the correctness of parameters
Acquisition Reports
- Check traffic source reports
- Confirm that UTM tags work
- Check that all channels are correctly identified
FAQ
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What is the difference between key events and conversions in GA4?
Key events are the new name for conversions in GA4. Functionally, it's the same thing: events you mark as critically important for your business. The renaming was done for better integration with Google Ads, where conversions have a different meaning.
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How many key events can be created in GA4?
Maximum 30 key events per property. I recommend using 5-10 most important events to not dilute the focus. Choose the actions that directly affect business results.
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Why do GA4 data differ from Universal Analytics?
GA4 uses a different attribution and calculation model. Main differences: event-based vs session-based, different session definitions, different unique user calculation logic. A difference of 10-20% is normal.
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How to set up call tracking in GA4?
Create a phone_click event that triggers when clicking on a tel: link. In GTM, set up a Click - Just Links trigger with a filter Click URL contains "tel:". Pass the phone number as an event parameter.
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Is Google Tag Manager needed for GA4?
GTM is not mandatory, but recommended. It simplifies event management, allows changes without developers, provides versioning. For complex setups, GTM is practically necessary.
