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5 GA4 Mistakes That Corrupt All Your Data

81% of GA4 configurations contain critical errors. Misnamed events, missing conversions, absent filters: here's how to fix them.

Greg-Jordan Metoui
Greg-Jordan Metoui
Founder & Data Expert · 20 avril 2026 · 2 min read

81% of GA4 configurations are incorrect

Since the Universal Analytics → GA4 migration, most businesses have partially or totally broken data collection. The reasons are multiple: rushed migration, lack of training, complexity of GA4’s event model.

Here are the 5 mistakes we find in 8 out of 10 audits.

Mistake 1: Events without parameters

GA4 relies on an event model. But sending a purchase event without value, currency, transaction_id and items parameters is like counting sales without knowing what was sold or for how much.

Mistake 2: No internal traffic filter

Your own visits, your agency’s, your developers on staging — everything is mixed with real traffic. Your engagement and conversion metrics are artificially inflated.

Mistake 3: Conversions are not defined

By default, GA4 marks no event as a conversion (except purchase since late 2023). If you haven’t explicitly defined your conversions, your conversion reports are empty.

Without Consent Mode V2, GA4 loses 100% of data from users who reject cookies. With Consent Mode, Google uses statistical modeling to fill the gaps.

Mistake 5: Ignoring Explorations

90% of GA4 users only look at standard reports. The real power of GA4 is in Explorations: cohort analysis, path analysis, advanced segments, funnel analysis.

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Greg-Jordan Metoui
About the author
Greg-Jordan Metoui
Founder & Data Expert chez chillmetrics

Expert en data, tracking et analytics depuis plus de 17 ans. Accompagne les entreprises dans la mise en place de leur stratégie de collecte et d'exploitation de données.

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