Apdex Guide

What is Apdex?

Apdex (Application Performance Index) is used to measure the performance of software applications.

Its purpose is to convert measurements into insights about user satisfaction, by specifying a uniform way to analyze and report on the degree to which measured performance meets user expectations. It is based on counts of "satisfied", "tolerating", and "frustrated" users, given a maximum satisfactory response time t, a maximum tolerable response time 4t, and where users are assumed to be frustrated above 4t. The score is equivalent to a weighted average of these user counts with weights 1, 0.5, and 0, respectively.

How does Apdex work?

The Apdex method converts many measurements into one number on a uniform scale of 0 to 1 (0 = no users satisfied, 1 = all users satisfied). The resulting Apdex score is a numerical measure of user satisfaction with the performance of enterprise applications. This metric can be used to report on any source of end-user performance measurements for which a performance objective has been defined.

Apdex T is the central value for Apdex—it is the response time above which a transaction is considered “tolerable.” You can define Apdex T values for each application, with separate values for app server and end-user browser performance. You can also define individual Apdex T thresholds for key transactions.