Traffic Quality
Also known as: Visitor quality
The composition of traffic rather than its size: intent match, commercial attachment, return behavior, durability, and source concentration.
Traffic quality is made of five checkable things: whether visitors land on pages that answer what they asked, whether their queries are attached to a decision, whether anyone returns on purpose, whether the traffic survives a pause in publishing, and how concentrated the sources are.
All five can be answered from data most properties already collect. None of them appear on a standard traffic dashboard.
Quality analysis has its own trap. Optimizing a property down to a small, high-intent audience can strip out the top-of-subject content that created the association in the first place. Definitional content is not worthless. The mistake is counting it as commercial traffic.