Inaccurate analytics can quietly distort your analytics and indeed revenue.

Even according to industry experts, 58% of business leaders rely on inaccurate data, leading to wrong decisions. With Google Analytics 4 (GA4) now the standard, ensuring your tracking setup is accurate is no longer optional, it’s critical.

Switching your data from traditional Universal Analytics (UA) to GA4 can get you access to additional features and data processing techniques. Performing a GA4 audit is essential for ensuring an accurate Data Collection, optimizing tracking and reporting, preventing data loss, and maintaining data quality at every step of reporting.


With the help of GA audit checklist, you can easily find hidden tracking problems, and make sure your data accurately reflects how users engage with your website or app.

Let's first start by going over the fundamentals.

A Google Analytics 4 (GA4) Audit: What is it?

A Google Analytics 4 (GA4) audit is considered a structured review of how a GA4 property has been implemented and configured to determine whether it is actually capturing, processing, and surfacing data as teams assume it is. In practice, it is guided by a GA4 Audit Checklist and uncovers issues such as partially fired tags, subtle configuration mistakes, misaligned goals, or data gaps that don’t break reports outright but quietly distort the insights used for analysis and decision-making.

GA4 Audit Checklist: 10 Key Areas to Review‍

Below is the full GA4 audit checklist that you need to make sure of before making the big decisions:

1. Setting Up Tracking Code

At first, ensuring that the tracking code is properly implemented on your website or app is paramount in GA4. The tracking code, known as the Global Site Tag (gtag.js) for GA4, must be placed on every page where you want to track user interactions.

  • Correct Placement: The GA4 tracking code should be placed in the <head> section of your HTML code for every page on your website. 
  • Implementation via Tag Manager: When GA4 is deployed through Google Tag Manager, the assumption is usually that “GTM handles it.” Preview Mode needs to be used across real navigation paths, not just the homepage, to confirm the tag behaves consistently.
  • No Duplicate Tracking: GA4 does not protect you from yourself here. One page should send data through one GA4 tag. What shows up instead are parallel setups, gtag plus GTM, multiple containers, or legacy tags left behind after migrations. Nothing errors out. Pageviews and events just inflate, and unless someone is looking closely, the distortion gets accepted as growth.
  • Unique Measurement ID: The Measurement ID is a small detail with outsized impact. Using the wrong one doesn’t break tracking; it quietly sends clean-looking data to the wrong property.
  • Debugging and Testing: You can use the "Google Tag Assistant" Chrome extension or GA4’s "Real-time" report view to test the tracking code and debug it instantly.

2. Configuring GA4 Property Settings

This is the part of GA4 most teams touch once and then never revisit. Currency, time zone, and linked Google services all sit quietly in the background, but they shape every report you look at. When these settings are off, nothing obviously breaks, but they stop lining up with how the business actually measures performance. A Google Analytics audit should treat these as foundational, not administrative.

  • A clear and consistent property name needs to be added.
  • Synchronize your reporting time zone with your business's time zone or the location of your audience.
  • Choose the correct currency for your property for recording e-commerce data.

3. GA4 Data Streams

Data streams define where data is coming from web, Android, or iOS and how GA4 interprets incoming events. They’re simple to create, which is exactly why they’re often set up quickly and left unchecked. In website analytics audits, it’s common to find streams that exist but don’t fully represent how users actually interact across platforms.

  • Correct Data Stream Configuration: The first step in a GA4 audit is confirming that the right streams exist and are tied to the right properties. Regardless of the platform you want to track, whether it’s a website or an app, you need to ensure that the appropriate data stream is in place. 
  • Stream URL (for Websites): Also, the data stream should have the correct URL for the site being tracked. This URL helps GA4 identify the source of the data and is critical for accurate session attribution. Make sure that the correct domain or subdomain is being tracked.
  • Enhanced Measurement Settings: GA4 provides automatic tracking for key user interactions such as page views, scrolls, file downloads, and outbound clicks through the Enhanced Measurement feature. Do not forget to enable Enhanced Measurement setting for your data streams, so that you get your analytics according to your tracking needs. 
  • App Data Streams: If you are tracking app data (iOS or Android), verify that the appropriate SDKs are installed in the app wherein the data streams are correctly configured. For mobile apps, this usually means implementing the Firebase SDK and confirming it’s actually sending data to the GA4 property you think it is. 
  • Cross-Domain Tracking: Cross-domain tracking becomes necessary the moment a user journey crosses domains for checkout, content, or support are typical examples. This is also where setups often look “mostly right” but still fail. Domains are added to the data stream, but linking isn’t consistent, referral exclusions aren’t behaving as expected, or only some domains are actually participating in the session. The result is fragmented sessions and attribution that resets mid-journey without anyone noticing.

4. Validating GA4 Data Settings

GA4 Data Settings rarely get much attention after initial setup, which is why they quietly cause long-term issues. These settings control how data is retained, how users are stitched together, and how information is shared across Google’s systems. When they’re wrong, the damage isn’t obvious; it just limits what you can analyze later or introduces gaps that can’t be fixed retroactively. A GA4 audit should slow down here and verify what’s been assumed.

  • Data Retention Settings: This determines how long user-level data is available for analysis. The default is often left untouched, and teams only realize the impact months later when historical comparisons or explorations are no longer possible. Changing retention doesn’t recover lost data, so this needs to be intentional, not accidental.
  • User-ID Setup: User-ID is frequently described as “enabled” when, in practice, it isn’t doing anything useful. Either the ID isn’t passed consistently, it changes between sessions, or it’s only implemented on a subset of interactions. When that happens, cross-device and logged-in behavior looks cleaner than it actually is, masking fragmentation rather than fixing it.
  • Google Signals: Google Signals is a feature in GA4 that enables cross-device tracking and provides additional demographic and interest data for users who have opted into personalized ads through their Google accounts. Verify if Google Signals is enabled in your property. If you rely on cross-device tracking or need richer audience data (like age, gender, or interests), activating Google Signals can provide valuable insights. 
  • Internal Traffic and IP Filters: Make sure that your GA4 property is filtering out internal traffic (from employees, developers, or team members) and other irrelevant traffic sources that could skew your data.

CTA

5. GA4 Audiences

Audiences are often treated as a downstream feature, but in a GA4 audit, they’re worth a careful look because they reveal how teams think users behave. GA4 makes it easy to create audiences, which is exactly why many of them exist without being well thought through. Make sure the audiences you’ve defined actually line up with how the business operates and how tracking is implemented, not just how it was described on a whiteboard. In GA4, audiences can be built from behavior, demographics, or events, but the flexibility cuts both ways.

  • Audience Setup: Each audience should be defined using criteria that reflect stable, well-understood events. In audits, labels like “high-value users” or “cart abandoners” are common, but the events underneath them often fire inconsistently or represent slightly different actions than assumed. The audience exists, but it doesn’t represent the group it’s named after.
  • User Conditions: Conditions need to be checked event by event. In audits, users are often included or excluded because a condition was based on an event that only fires in certain scenarios, or on parameters that aren’t always present. The logic is technically valid, but the resulting audience is incomplete or skewed.
  • Audience Size: Audience size is a practical check. Very small audiences usually point to overly strict or broken logic. Very large ones often mean the criteria are too loose. Neither is wrong in isolation, but both reduce the audience’s usefulness for analysis or activation.

6. Data Layer and Custom Definitions

Verify if custom dimensions, custom metrics, and data layers are set up correctly for personalized data collection. If you’re relying on custom data such as user attributes, product details, or other non-standard fields, the data layer needs to be doing real work, not just existing. In audits, this is where intentions and reality often diverge. Parameters are pushed inconsistently, values change formats, or key fields only appear in some events. GA4 doesn’t flag this as a problem; the data just becomes hard or impossible to use. Custom dimensions and metrics also need to be registered correctly, or the data is collected but never surfaces in reports. When this setup is off, custom events technically fire, but the context teams expect to analyze is either missing or unreliable.

7. GA4 Event Tracking

Make sure custom events are in place and still reflect the actions they were created to measure. In audits, events for things like login clicks or button interactions often exist but fire inconsistently, trigger in places no one intended, or no longer match the current product flow. GA4’s auto-collected events, like page views, scrolls, and outbound clicks, usually fire without issue, which is why they’re rarely questioned. The audit needs to confirm that both custom and standard events fire in the right contexts and represent real user actions, not just that they show up in GA4.

  • Standard Events: Standard Events: Built-in events like page_view, scroll, outbound_click, file_download, and session_start are usually there, which is why they’re rarely questioned. In audits, the issue isn’t absence; it’s behavior. Scroll fires where it adds no value, outbound clicks miss the links that matter, and session-related logic produces patterns that don’t match real navigation. Nothing looks broken, but the signals are off.
  • Custom Events: Custom events are where GA4 configurations slowly lose discipline. Clicks, form submissions, and video views get tracked, then redefined, then partially reused. Names stay the same while meaning changes, or triggers expand to cover edge cases no one intended. Custom events are crucial for capturing actions specific to your business. Verify that custom events are set up correctly. 

8. Key Event Tracking

Check for key events that might not be working or are set up incorrectly. If applicable, verify if eCommerce tracking is enabled. Specific key events, like form submissions for demos, contacts, and gated content, as well as link clicks for emails and phones, should be tracked.

Common key events and actions to check:

E-commerce actions: purchase, add_to_cart, begin_checkout

Lead generation actions: sign_up, form_submission, newsletter_signup

Engagement actions: video_start, video_complete, social_sharing

9. GA4 Product Links

When conducting a GA4 audit, Product Links cover how GA4 is connected to other Google products such as Google Ads, BigQuery, and Search Console. On paper, GA4 is built to integrate cleanly, which is why these links are often set up once and then ignored. In audits, the connections usually exist, but they’re rarely correct end-to-end. Accounts are mis-scoped, links point to the wrong properties, or only part of the data is actually shared. Nothing breaks outright. Data continues to flow, but not in the way reporting, attribution, or downstream analysis quietly assumes. When product links aren’t reviewed, campaign performance, conversions, and cross-channel analysis end up resting on partial or misaligned data.

GA4 Product Links

10. GA4 Reporting and Explorations

Reporting and Explorations are where configuration issues finally surface, because this is where teams try to answer real questions. During an audit, these sections matter less for how they look and more for what they reveal about the underlying data. Reports can fill up with data and still be misleading, and explorations can be built correctly while pointing to the wrong conclusions. GA4 doesn’t stop you from analyzing flawed inputs; it just reflects them.

  • Standard Reports Configuration: Core reports like traffic acquisition, engagement, monetization, and conversions should be reviewed for coherence, not just activity. In audits, these reports often contradict each other in small ways, which is usually a sign of upstream tracking or configuration issues rather than real user behavior.
  • Custom Reports: Custom dimensions, metrics, and filters need to be checked against how data is actually collected. It’s common to find reports built on parameters that fire inconsistently or were changed after the report was created, leaving the output technically valid but practically unreliable.
  • Explorations Setup: Funnels, paths, and cohorts tend to expose weaknesses quickly. Broken steps, unexpected drop-offs, or empty segments are usually symptoms of earlier tracking decisions rather than user behavior.
  • Real-Time Reports: Real-time data is useful as a quick signal, not a source of truth. That confidence is often misplaced. Real-time confirms that something fired, not that it will be processed, attributed, or reported correctly later.
  • Reporting Access and Permissions: Access doesn’t change how data is collected, but it does change how it’s interpreted. Inconsistent permissions lead to teams working from different views of the same property, or worse, from assumptions based on partial access.

Conclusion

A Google Analytics 4 audit isn’t about fine-tuning or optimization. It’s about verification. It’s the work of checking whether the data being collected and reported can actually support the decisions being made from it. Walking through a GA4 audit checklist from tracking and property settings to events, audiences, and reporting forces a review of assumptions that usually go unchallenged and configurations that no longer match how the business functions.

Regular audits make issues visible while they’re still manageable, before they harden into accepted “truth” and start shaping strategy or performance decisions. GA4 rarely fails loudly. It drifts. Auditing is how you notice the drift while it’s still correctable.

Frequently Asked Questions

Why is a GA4 audit important?

A GA4 audit matters because many tracking issues don’t announce themselves. Data can look stable while being incomplete, inflated, or misattributed. Auditing is how you reduce the risk of making decisions on numbers that only appear reliable.

How do I check if my GA4 tracking code is working?

Tag Assistant, GA4 real-time reports, and GTM Preview Mode are useful starting points. In practice, they confirm presence, not correctness. An audit goes further by checking consistency across pages, events, and reporting over time.

How do I integrate GA4 with Google Ads?

GA4 connects to Google Ads through Admin → Product Links → Google Ads. The integration itself is straightforward. The harder part is verifying that conversions, audiences, and attribution behave the way teams expect after the link is in place.