<span lang="en">During the 90's the exponential growth of the number of Internet users led to the birth of many ISPs and data operators. Nowadays, after the technological bubble, only some of them survive. Since prices have reached the lowest limit, some kind of service quality differentiation between competitors is a must. Unfortunately, QoS measuring methods don't always agree with users' expectations. Moreover, many times data operators don't know how to improve the quality that users perceive. Any investment on infrastructures seems to result on an improvement, but there are no guarantees. This article describes the effort of a group of Spanish Universities towards the definition of a method to set up and measure the relationships between users' satisfaction and network parameters. The model developed would allow both ISPs and legislators to control the degree of users' satisfaction, as well as how any change in network parameters results on a variation of their perceptions.</span>