The silent tracking failure almost nobody catches: events lost during migration or refactoring.
You rewrite a screen. Or you refactor a component. Or a flow gets rebuilt because the old code was messy. The new implementation works - tests pass, features ship, QA signs off.
But somewhere in the rewrite, two or three tracked events quietly didn't make it across. The analytics call that used to fire on "react" doesn't exist in the new code. The property that used to get passed on the checkout event was in the old version but not the new.
Analytics keeps reporting numbers. Dashboards look normal. Nobody notices anything is wrong.
Six months later someone asks "why is our react rate dropping?" or "why did checkout attribution get weird around Q2?" - and nobody has an answer, because the regression happened inside a refactor nobody thought to check for tracking.
This is almost impossible to catch by reading new code alone. The new code looks complete. It compiles. It ships features. The bug is in what's not there anymore.
The only reliable way to catch it is comparing what was tracked before against what's tracked now. That's a specific kind of diff that normal code review doesn't do - reviewers check that the new code works, not that it preserves every analytics call from the old code.
If you've shipped any significant refactor in the last 12 months and haven't specifically checked tracking parity, there's a nonzero chance events regressed and you're looking at incomplete data without knowing it.
#ProductAnalytics #TechnicalDebt
Originally published on LinkedIn by X91 Tech.
