ИСТИНА

A computer-implemented method and a server with a processor are presented for determining a trend of a user engagement metric with respect to a web service. The method comprises receiving a plurality of user device requests, providing a test version of the web service to a test group and a control version of the web service to a control group, acquiring an amplitude metric and a phase metric for each one of the user devices of at least the test group, determining average group metrics, and determining the trend of the user engagement metric with respect to the web service, the determining the trend being based on analyzing of the control average amplitude metric and the test average amplitude and phase metrics.