*** Welcome to piglix ***

Apdex


Apdex (Application Performance Index) is an open standard developed by an alliance of companies. It defines a standard method for reporting and comparing the performance of software applications in computing. 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.

When engaging in application performance management, for example in the course of Website monitoring, enterprises collect many measurements of the performance of information technology (IT) applications. However, this measurement data rarely provides a clear and simple picture of how well those applications are performing from a business point of view, a characteristic desired in metrics that are used as key performance indicators. Reducing measurement data to a single well understood metric is the ideal way to track and report on Quality of experience. Reporting several different kinds of data often confuses the picture, rather than clarifying it.

Measurements of application response times, in particular, can be obtained from many different measurement tools, yet once gathered, they are difficult to evaluate because:

The Apdex method seeks to address these problems.

Proponents of the Apdex standard believe that it offers a better way to measure what matters. 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.

The Apdex formula is the number of satisfied samples plus half of the tolerating samples plus none of the frustrated samples, divided by all the samples:

where the sub-script t is the target time, and the tolerable time is assumed to be 4 times the target time. So it is easy to see how this ratio is always directly related to users' perceptions of satisfactory application responsiveness.


...
Wikipedia

...