Tracking Gap
A tracking gap is any place a real revenue event in the business fails to register, or registers incorrectly, in the systems used to make spend or reporting decisions — missing pixels, broken server-side events, attribution mismatches, identity-resolution failure. Gaps make ad platforms optimise toward the wrong audience and make internal reports lie.
Definition
Tracking gaps usually live between systems: the website handing off to the tag manager, the tag manager handing off to the ad platform, the ad platform handing off to the CRM. Each handoff is a candidate gap.
Why it matters
A tracking gap is one of the cheapest, highest-leverage things to fix. The same campaign with clean tracking spends to a different audience than the same campaign with broken tracking — usually a much better one.