Google Analytics Data Quality: Health Check Dashboard for E-Commerce & Performance Marketing simplifies debugging

Many marketing teams are familiar with this: The GA4 numbers feel “somehow wrong.” Campaign reports don’t match shop revenue, the ratio of (direct) / (none) is increasing, conversions are disappearing – and the feeling lingers: ” Our Google Analytics numbers are wrong. “

Typical questions in everyday marketing are: “Why are our GA4 figures no longer accurate?”, “Why is the direct/none traffic so high?”, or “Why aren’t our e-commerce events appearing in the GA4 report?”. Ultimately, more discussion revolves around the accuracy of the data than around the next steps in performance marketing and e-commerce.

This is exactly where GA4 Health Checks come in: A dashboard that continuously checks your GA4 data quality and shows you where something is going wrong and how much this affects you in everyday life.

In this article, I’ll show you what a GA4 Health Check Dashboard can do, which checks it contains, and why it’s particularly worthwhile for marketing managers to organize things in a structured way.

What is a GA4 Health Check Dashboard – and why are your GA4 figures often incorrect?

A GA4 Health Check Dashboard is a central quality cockpit for your tracking:

• It is based on the GA4 raw data in BigQuery .
• It contains predefined data quality checks .
• It runs automatically every day and shows you deviations and problems.

Instead of jumping through dozens of GA4 reports, you can see at a glance:

• How healthy your sessions are (session quality)
• How well your marketing channels are attributed (attribution)
• Will all the major events fire (expected events)?
• How accurately the e-commerce funnel is measured
• Which events are incomplete or faulty (event quality)

For you as a marketing manager, this means: You don’t have to debug yourself , but receive clear indications of where something is wrong – and how urgent it is.

Check 1: Session consistency – stable foundation for all reports

Sessions form the basis of every analysis in GA4. If something is wrong here, all subsequent KPIs are affected: user numbers, campaign performance, conversion rates.

The session consistency health check verifies, among other things:

• Whether sessions are clean withsession_start start
• Whether there will be at least one in the sessionspage_view gives
• Whether new users (session_number = 1 ) afirst_visit Have an event
• Whether it is auser_engagement Event gives (signs of real interaction)

This results in a Session Quality Score per day.

Typical problem patterns

• Tracking code not integrated everywhere
  Example: The agency’s landing pages use Google Analytics 4, but the shop’s checkout has an older setup. Result: Purchases only partially appear, and reports seem incomplete.
• Consent banner blocks events
  Visitors reject tracking or only give their consent late. If GA4/Tag Manager is incorrectly integrated, key events such as… will be missing.page_view orsession_start .
• Faulty GTM configuration
  Tags only fire under certain conditions – or not at all, because a trigger has been changed.

In the dashboard, you can see this, for example, in the percentage of sessions without…session_start or **page_view If the session quality score is consistently low or rising, then it’s clear: before optimizing your next campaigns, you first need to repair the foundation.

Check 2: Traffic attribution – Clarity about where users really come from

If you want to know which channel is truly generating revenue , you need reliable acquisition data. Especially in performance marketing, it’s crucial that you allocate budgets based on solid figures, not just perceived ones. GA4 primarily uses this for that purpose.session_start Events with campaign information.

Why (direct) / (none) traffic in GA4 is increasing

A classic example: The percentage of (direct) / (none) traffic increases, while campaigns are clearly still running. Often, this isn’t due to actual user behavior, but rather problems with UTM parameters, redirects, or consent settings. This is precisely where the Health Check Dashboard comes in – it shows you how much traffic is truly “unattributed”.

The health check for traffic attribution looks at, among other things:

• Total number of sessions
• Sessions without a clear attribution (e.g., Direct/Unattributed)
• Share of Google Ads sessions (e.g., withgclid )
• Distribution across Organic, Social, Email, Referral, Shopping, etc.
• An Attribution Quality Score : How many sessions have a meaningful marketing source?

Where attribution frequently breaks down

• Incorrect or missing UTMs
  Newsletters without UTM parameters are recorded as “direct”. Paid social media is recorded as “referral” or “(other)”.
• Redirects & Self-Referrals
  Payment providers, redirects, external forms – if campaign information isn’t included here, many “session restarts” with self-referrers occur. The dashboard counts these separately so that the attribution score doesn’t suffer unnecessarily.
• Problems with Consent & gclid
  If the consent mode or tagging is not set up correctly, thegclid They will be lost – and Google Ads sessions will no longer appear as such.

The result: You ca n’t properly demonstrate campaign ROI , budgets are questioned or wrongly cut. The Health Check makes these gaps visible and shows whether it’s an isolated incident or a structural problem.

Check 3: Expected events – are the signals firing that you’re spending your money on?

Every company has a number of core events that are essential for reporting:

• Standards such assession_start ,page_view , first_visit
• Important micro-conversions (e.g.generate_lead ,sign_up )
• E-commerce events such asview_item ,add_to_cart ,begin_checkout , purchase

In the GA4 Health Check, these are maintained in a list of expected events . The check then verifies the following daily:

• How many of the expected events actually occur
• What is the completeness rate ?
• Which events are completely missing?

Typical situations in which events “disappear”

• Relaunch or redesign
  New templates, new buttons, new URLs – and the old tagging no longer works. Suddenly, it becomesadd_to_cart only recorded on a portion of the product detail pages.
• New checkout or payment process
  The service provider or system is being changed, and of all things…purchase orbegin_checkout were forgotten during the renovation.
• Changes to the form or lead process
  The lead form has been moved to a new page, but thatgenerate_lead The event remained stuck with the old format.

Without a health check, problems often go unnoticed for weeks – when key performance indicators in reporting suddenly plummet. The dashboard lets you see daily whether all critical events are still active.

Check 4: E-commerce funnel – a realistic picture of e-commerce tracking

A properly measured funnel is crucial for e-commerce. If the sequence of events is incorrect or intermediate steps are missing, you lose the foundation for conversion optimization.

The e-commerce funnel check verifies, among other things, whether the logical sequence is followed:

view_item → add_to_cart → begin_checkout → add_shipping_info → add_payment_info → purchase

The dashboard analyzes, for example:

• add_to_cart_without_view_item – Items in the shopping cart without having previously viewed a product
• checkout_without_add_to_cart – Checkout started without a shopping cart event
• purchase_without_checkout – Purchase without begin_checkout
• purchase_without_add_to_cart – Purchase without shopping cart event
• total_ecommerce_sessions,sessions_with_purchase ,sessions_with_checkout and percentage shares of the inconsistencies
• A Funnel Quality Score that places greater emphasis on purchase-related errors.

What lies behind such inconsistencies?

• Quick Buy / Express Checkout
  “Buy now” buttons that simply skip events result in purchases without shopping cart events.
• Incomplete DataLayer
  DataLayer events are not triggered on all relevant pages or do not contain all the necessary information.
• Incorrect event positions
  Events fire on the wrong side or even when the checkout is loading, before the user has done anything.

The consequence: Funnel reports look better or worse than reality. A/B tests are misinterpreted. With the Health Check, you can clearly see where the funnel breaks down technically – and fix these issues together with your tech team/agency.

Check 5: Event quality – clean e-commerce data instead of noise

Not only the “whether” but also the “how” of the events is crucial. GA4 expects certain mandatory fields for many e-commerce events. If these are missing, evaluations become inaccurate or completely unusable.

The event quality check goes into detail at the event level and examines, among other things:

• Whether an items array exists (for all e-commerce events)
• Whetheritem_id anditem_name are set
• Whetherprice andquantity are present
• Whethervalue andcurrency be transmitted correctly
• Whethertransaction_id is set for purchases and refunds
• Whether optional but important information is missing (e.g.shipping_tier ,payment_type , List info)
• Are there any suspicious values such as(not set) or empty strings

For each faulty event, the dashboard provides:

• Event name and date
• User and session context (anonymized)
• A list of the errors found
• Debug information about items and parameters

Check 6: Session Restart Buckets

Another element in the dashboard is the Session Restart Buckets . Here you can see after how many minutes or hours users with the same domain as the referrer return because their original session has expired. Based on the distribution across the buckets, you can assess whether the default session duration of 30 minutes is appropriate for your site – or whether it’s generating many “artificial” restarts. The goal is to find a setting that avoids a significant number of restarts, allowing Google Analytics 4 to better reflect the actual session movement of users and making your analytics on engagement, funnels, and campaigns more stable.

What this is good for in everyday life

• You can reliably analyze product performance (which products are actually seen, added to the shopping cart, and purchased?).
• Your team can accurately evaluate ROAS and campaign performance becausevalue ,currency andtransaction_id are correct.
• Agencies and developers receive concrete information about which fields are missing – instead of a vague message “the tracking is incorrect”.

Real-time debugging with intraday tables

A practical advantage of the GA4 Health Check Dashboard: Thanks to intraday tables, many errors can be detected and debugged almost in real time.

Instead of waiting a day for the data to arrive in the standard export, you can check for anomalies on the same day.

• whether a new event fires correctly,
• whether a changed trigger in Tag Manager works as planned or
• Whether after a shop or checkout update, e-commerce events run smoothly.

For performance marketing teams, this means: less flying blind after deployments , faster corrections and significantly less risk of advertising with broken tracking for several days.

How a GA4 Health Check works in practice

In practice, our GA4 Health Check is deliberately streamlined and pragmatic – without a large consulting project in the background.

1. Contact & brief inventory
   You contact us with your GA4 problem (e.g., numbers seem wrong, (direct) / (none) is too high, e-commerce tracking doesn’t make sense) and we clarify in a short conversation what exactly you are concerned about.
2. Definition of the most important events
   Together, we prioritize the events and conversions that are most important to you – for example, leads, e-commerce events, or key micro-conversions. These are then incorporated directly into the Health Check Dashboard as “expected events”.
3. Access to Google Cloud & BigQuery
   You provide access to your Google Cloud project. Prerequisite: Your GA4 property already writes its data to BigQuery . If this isn’t already set up, we’ll assist you with the necessary steps and settings.
4. Installation & rollout of the Health Check Dashboard
   We will integrate our pre-configured GA4 Health Check installation into your Google Cloud project. Based on the raw GA4 data, the checks will be performed and the dashboard will be built.

Result: Within a short time, you have a running GA4 Health Check Dashboard that monitors your GA4 data quality daily – without having to struggle through technical details or data engineering.

For agencies and tracking providers, we also offer a compact training package, after which you can independently use, interpret and integrate the GA4 Health Check Dashboard into your own client setups.

Typical findings from GA4 Health Checks

Some examples that repeatedly arise in practice:

• Newsletter campaigns as Direct
  UTMs are missing or incorrectly configured. The dashboard shows a high percentage of “direct” entries, while at the same time the attribution score is decreasing.
• Checkout only starts measuring from step 3 onwards.
  A relaunch means that previous steps are no longer tracked. The conversion rate suddenly appears much better – in reality, only the previous funnel stages are missing.
• E-commerce events without value/************************currency
  Sales are visible in the shop, but neither the shopping cart values nor the ROAS are correct in GA4. The event quality dashboard clearly shows which events are missing values.

A structured health check can not only identify such problems but also monitor them over time : Is it improving? Is it remaining stable? Do old errors reappear after changes?

Conclusion: Without clean data, all decisions are uncertain.

As a marketing manager, you make daily decisions about budgets, campaigns, and measures. If the data foundation is shaky, every optimization becomes somewhat of a gamble .

A GA4 Health Check dashboard helps you regain confidence in your numbers :

• You can see at a glance how healthy your GA4 data is.
• You can recognize early on if something breaks after relaunches or changes.
• You can make well-founded arguments to management and stakeholders.

At webmasterei-prange.de we support you in this,

• to set up a GA4 Health Check Dashboard,
• to translate the results into understandable recommendations for action and
• to implement the necessary adjustments together with your team or agency.

If you feel you can no longer really trust your GA4 numbers, a structured health check is often the fastest way back to a reliable data basis.

Next step: Sign up for a short, non-binding initial check – and together we’ll take a look at the data quality in your GA4 setup.