How Apdex Works

Apdex provides a numerical measure of user satisfaction with the performance of enterprise applications. Apdex reports are arrived at using a four-step method.

Step 1 – Select Target Time

Define a target response time of T seconds.  Response times between 0 and T are considered satisfactory by the users within a business scenario.

Step 2 – Measure Performance

Measure performance and place each measurement into one of three user-perceived performance zones: satisfied (Sat), tolerating (Tol), or frustrated.  The satisfied zone is defined in Step 1.  Frustrated times are above F seconds, where F=4T.  Tolerating times are between T and F.

Step 3 – Apply the Apdex Formula

Sum the incidents of response times that fall into each zone, and divide by the total number of measurements using the formula:

Step 4 – Show Results

Show the Apdex Index value (on a scale of 1 to 0) together with the corresponding threshold T.

Apdex is an open standard developed by the Apdex Alliance.  See www.apdex.org to learn more.