Frequently asked questions
- Is it true that QoE is purely subjective?
- Is there a single definition of QoE that everyone accepts?
- Is QoS relevant to QoE?
No. Some work to date on QoE has concerned subjective measurement of experience and QoE is defined by the ITU in terms of user perception and/or user satisfaction. However, data about QoE would be more comprehensive and potentially more valid and reliable if objective, as well as subjective, user measures are included. For example, user effectiveness and efficiency can be measured objectively in addition to subjective user satisfaction. This is consistent with accepted good practice in psychological research that does not rely on opinion and self-reported behaviour when objective measures of human behaviour can be collected.
Objective QoE data include measures of the communication process and the task outcome (see the related tutorial here on “User test measures”). Example measures of the process of communication are the number of communication interruptions and the amount of turn-taking. Example measures for the outcome of communication are the length and accuracy of the task performed.
It is because it is argued that QoE should extend beyond subjective measures of user-perception and user satisfaction to include objective measures of communication process and outcome that this site and ETSI TR 102 643 provide an alternative definition, in addition to the ITU-T definition.
Not at the moment of writing. In the first chapter we offer a definition of QoE from ETSI TR 102 643. It is a definition also promoted in the IEEE Network magazine’s special edition on the QoE of network services (Brooks and Hestnes, in press).
Partly because QoE is a recent and evolving concept, there are different definitions of QoE across current ITU, ETSI and other technical and scientific literature and deriving a harmonised definition of QoE requires further work.
It is because it is argued that QoE should extend beyond subjective measures of user-perception and user satisfaction to include objective measures of communication process and outcome that this site and ETSI TR 102 643 provide an alternative definition, in addition to the ITU-T definition that is limited to describing QoE as subjective.
QoS (Quality of Service) is very relevant to QoE because a QoE measure needs to be stated together with the technical conditions of a communication service if it is to be useful for stakeholders. If a service should be improved for customers or end-users, stakeholders need to know that the QoE level is not good enough and should be able to decide which one or more technical QoS parameter could be improved in order to achieve higher QoE. Consequently, QoE should be expressed in QoS terms.