Tagging Strategy and Data Quality

Which events you need to track so your CRO decisions stand on solid ground, and how you manage data quality as a decision-maker.

You know the events that are indispensable for CRO decision-makers.

• You can assess the data quality of your setup.
• You set priorities for new events

Every event you track costs resources: setup, maintenance, documentation.

• Too many events create data noise and hide the signals that actually matter.
• Too few events leave gaps in your analysis and lead to the wrong conclusions.

One: Funnel events. Page views, cart, checkout steps, purchase.

• Two: Engagement events. Scrolls, CTA clicks, video interactions.
• Three: Micro-conversions. Newsletter sign-up, PDF download, consultation form.
• Four: Error events. Form errors, 404 hits, dead clicks.
• Five: External events. Outbound clicks, social shares, partner links.

A shop only tracks the purchase, not the individual checkout steps.

• The result: it can see the checkout drop-off rate, but not where users are actually leaving.
• Once the checkout step events are set up, targeted test hypotheses start to emerge.

Completeness: are all business-critical events being captured?

• Accuracy: are events firing in the right places, and only once?
• Consistency: are events named and measured the same way across devices and platforms?
• Timeliness: are the events up to date with the current state of your shop?

A shop suddenly sees twice as many purchases in GA4 as are actually recorded in the backend.

• The cause: the purchase event was firing both in the shop code and through GTM.
• The result: every conversion-based decision was wrong until the issue was fixed.

High: events directly tied to revenue or conversion.

• Medium: events that generate hypotheses or segment tests.
• Low: events used for tracking or secondary analysis only

Every event needs a clear name, a purpose, and an owner.

• Documentation prevents events from being forgotten or built in twice.
• It's also the foundation for onboarding new team members and agencies.

List the ten most important events in your shop.

• Evaluate each event based on completeness, accuracy, consistency, and timeliness.
• Identify the three biggest gaps and define your requirements.

GTM lets you test new events quickly before they go live.

• Preview and debug mode help you catch errors before publishing.
• A controlled approval process through GTM reduces data quality issues.

One shop had over 50 events but no clear prioritization.

• After applying CRO prioritization, the team focused on eight critical events.
• The data quality of those eight events improved dramatically, and so did the quality of their A/B tests.

Reality: More events often mean more noise and less clarity.

• Not every click behavior is strategically relevant.
• Eight clean events beat fifty half-baked ones.

We need clean funnel events for every checkout step through to purchase.."

• Every new event must be documented before it goes live.."
• Once per quarter, we review the data quality of all CRO-relevant events.."

Shops with clean tracking make better decisions.

• Shops with clean tracking can evaluate tests faster and with greater validity.
• Tracking quality isn't an IT topic; it's a strategic asset.

Focus on CRO-relevant events and prioritize by business value.

• Evaluate data quality based on completeness, accuracy, consistency, and timeliness.
• GTM and an approval process are your quality gates.

Work with your team to define the eight to ten most important CRO events.

• Require event documentation and regular quality reviews.
• Always tie new events to a specific CRO question or hypothesis.

In the next module, we connect GTM with A/B testing: how Tag Manager and your testing tool work together so tests run faster and cleaner.

Test your knowledge.

Next module: GTM and A/B testing working together