5 GA4 Setup Mistakes That Are Costing You Data

Google Analytics 4 is a fundamentally different tool from Universal Analytics. The event-based model is more flexible, but it also means there are more ways to get the setup wrong. Here are the five mistakes I see most often.

1. Not Setting Up Custom Events

GA4's enhanced measurement captures some events automatically, but it misses the interactions that matter most to your business. If you're not tracking form submissions, CTA clicks, video engagement, or scroll depth with custom events, you're flying blind on user behavior.

2. Ignoring Data Streams Configuration

Many setups have duplicate data streams or misconfigured domains. This leads to inflated session counts and broken user journeys. Check your data streams — you should have exactly one per platform.

3. Missing Cross-Domain Tracking

If your user journey spans multiple domains (main site → checkout → thank you page), you need cross-domain tracking configured properly. Without it, each domain transition creates a new session, breaking your funnel data.

4. Not Using Google Tag Manager

Implementing GA4 directly in your site code makes it rigid and developer-dependent. GTM gives you the flexibility to add, modify, and debug tracking without touching your codebase. It's not optional — it's essential.

5. Skipping Conversion Configuration

Events don't become conversions automatically in GA4. You need to explicitly mark which events are conversions and ensure they're firing correctly. I've seen accounts running for months without any conversions configured.

The Fix

Each of these issues is fixable, usually within a few hours of focused work. The key is knowing what to look for and having a systematic approach to implementation.

Start with an audit of your current setup, prioritize the gaps, and implement fixes methodically. Your future self (and your marketing budget) will thank you.