The Most Common Mistakes in GA4 Setup

Google Analytics 4 (GA4) is the most powerful data analysis tool in modern digital marketing. But how accurate the numbers you see in the panel actually are depends on the quality of your setup. A faulty configuration leaves your entire advertising strategy resting on the wrong data.

Core configuration and data flow errors

• Duplicate code setup: Adding the code to the site manually while also activating GA4 through GTM or a WordPress plugin. It causes the data to be counted twice.

• Leaving the data retention period untouched: By default, GA4 sets data retention to 2 months. If you don't raise it to 14 months in the settings, you won't be able to pull detailed historical reports.

• Mismanaging enhanced measurement: Events GA4 tracks automatically, such as file downloads and site search, can clash with your site's own dynamics and produce misleading data.

Event measurement and conversion tracking mistakes

• Case sensitivity errors: GA4 event names are case sensitive. It reads Form_Submit and form_submit as two different events and splits your reports.

• Marking every event as a conversion: Marking every scroll or simple button click on the site as a "conversion" keeps your ad algorithms from optimizing.

• Not defining custom dimensions: If you don't register the parameters you send through GTM, such as button name or click location, as a "custom dimension" in the GA4 panel, that data won't show up in your reports.

E-commerce tracking errors: why does your revenue look incomplete?

On e-commerce sites, these configuration errors are what lie behind revenue in the panel not matching revenue in the bank panel:

• Missing currency: When the price is pulled from the data layer without the currency being reported to GA4 as TRY or USD, the data can't be processed.

• Wrong number format: Product prices sent as 150,00 (with a comma) can't be read by GA4. They have to reach the system directly as 150.00, in number format with a dot and no quotation marks.

• Using old UA code: Connecting a data layer architecture left over from the Universal Analytics (UA) era straight to GA4 causes product arrays (items) to be read incompletely or incorrectly.

Referral exclusion list and spam traffic problems

• Not excluding payment gateways (PayTR, iZico, etc.): When the user pays and returns to the site, GA4 sees the source behind the sale not as "Google" or "Meta" but as the payment provider. That makes measuring your ad performance impossible.

• Not excluding your own domain: If you don't exclude your site's own domain from the referral list, sessions keep breaking while the user browses the site and you end up with an artificial traffic increase.

Fixing GA4 errors and professional support

If you're getting no data after your GA4 setup, or you have doubts about how accurate the numbers in your panels are, it's time to run your data through a professional filter.

To avoid building an ad budget on faulty analysis and to protect the health of your data, visit our Google Analytics 4 Setup and Optimization page or get in touch with us.

Frequently asked questions

1. Why am I getting errors in my GA4 setup? Usually because the code has been added to the website in more than one way (both a plugin and manually), because Google Tag Manager triggers were set up incorrectly, or because of structural gaps in the data layer (dataLayer).

2. Why is GA4 undercounting data? Users rejecting cookie consent, an empty referral exclusion list, or price and currency parameters on the purchase page that don't meet technical standards all lead to undercounted data.

3. How do I set up GA4 correctly? The soundest approach is to build the whole structure through a Google Tag Manager (GTM) container instead of touching the site code directly, standardize event names in lowercase, and exclude payment gateways from the referral list.