Are your events describing real customer behaviour, or are they contaminated by internal visits, bots, payment gateway redirects, or data that will age out before you need it?
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Internal traffic filter setup
Screenshot of GA4 Admin Data Filters with an active internal traffic filter: IP rule set, State Active (not Testing). Callouts mark the two most-misconfigured settings: a filter left in Testing state, and an incorrect IP range.
| Check | What to look for | How to verify | Fix if failing |
|---|---|---|---|
| Internal traffic filter | Filter exists and is Active (not Testing) | Admin: Data Settings: Data Filters, State column | Create an internal traffic IP rule; set the filter Active |
| Data retention | Set to 14 months, not the default 2 | Admin: Data Settings: Data Retention | Change to 14 months (not retroactive, so do it now) |
| Referral exclusions | No phantom referral sessions from payment gateways or third-party portals | Acquisition report: unusual Referral domains with many sessions and zero conversions | Add the domain under Admin: Data Streams: Configure Tag: Unwanted Referrals |
| Bot filtering | Google's bot and spider filtering is on | Admin: Data Settings: Data Filters, check for the bot filter | Enable in property settings (on by default in new properties) |
| PII in event data | No emails, names or identifiable user IDs in event parameters or page paths | DebugView: parameter values on form_submit and page_view | Scrub in GTM before the hit fires; never pass raw form values as parameters |
| Cross-domain (if applicable) | Sessions don't break between domains (e.g. main site to booking subdomain) | Navigate between the domains and check whether a new session starts | Configure cross-domain measurement under Admin: Data Streams: Configure Tag: Configure Domains |
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Before/after: removing internal traffic
Side-by-side chart of sessions and conversion rate before and after activating the internal traffic filter. Before: 14%, with agency IP visits included. After: 3.2%, reflecting real customer behaviour. Agency visits inflate conversion rate on low-traffic sites.
Data retention is the silent killer. Two months is long enough to fool you into thinking everything's fine (you can see recent data) but too short for year-over-year comparisons, and you lose data before a client asks for it. Change it on the first day you access any property.