What Is an Apdex Threshold?

An Apdex threshold is a chosen response-time target, often called T, that splits requests into satisfied, tolerating, and frustrated buckets. Requests at or under T are satisfying, those up to four times T are tolerating, and slower ones are frustrating. The Apdex score then condenses those buckets into a single number between zero and one.

Why it matters

Picking the threshold defines what "fast enough" means for a service. It turns a latency distribution into one comparable score, but the choice of T drives whether that score is meaningful.

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