ApDex

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

ASM

This is how ApDex is calculated in Synthetic Monitoring:

Satisfied Count = Total count of Info samples

Tolerating Count = Total count of Warning samples

Frustrated Count = Total count of Errors and Failed samples

Apdex = (Satisfied Count + Tolerating Count / 2) / (Satisfied Count + Tolerating Count + Frustrated Count)

New Relic

This is how ApDex is calculated in New Relic:

Apdex = (Satisfied Requests + (Tolerating Requests / 2) ) / Total Number of Requests

More Information

More information is available at http://www.apdex.org/