Abstract: A method of monitoring the level of performance of a software application running on a network-attached computing device, comprises monitoring information exchange at least one station on the network; measuring at least two performance indicator metrics, such as delay, jitter, loss, response time, throughput, goodput, and object size; and deriving an indicator parameter from a non-linear combination of the indicator metrics. A transformation may be applied to each indicator metric to obtaining a corresponding derived value, and the derived values then additively combined, to obtain the said indicator parameter. The transformation has a first region in which the derived value depends relatively weakly on the corresponding metric, and a second region, in which the derived value depends relatively strongly on the corresponding metric. A score value may be entered by a user, indicative of the user's perception of the performance of the software application, and compared with the derived indicator parameter.