Quality of experience
From Wikipedia, the free encyclopedia
Quality of Experience (QoE), some times also known as "Quality of User Experience," is a subjective measure of a customer's experiences with a vendor. It looks at a vendor's or purveyor's offering from the standpoint of the customer or end user, and asks, "What mix of goods, services, and support, do you think will provide you with the perception that the total product is providing you with the experience you desired and/or expected?" And then asks, "Is this what the vendor/purveyor has actually provided?" If not, "What changes need to be made to enhance your total experience?"
It is related to but differs from Quality of Service (QoS), which attempts to objectively measure the service delivered by the vendor. It is tied closely to the black and white of a contract and measures how well the vendor lives up to its end of the bargain.
A vendor/purveyor may be living up to the terms of a contract's language, thus rating high in QoS, but, the users may be very unhappy, thus causing a low QoE. Conversely, the users may be very happy with a product or a vendor, resulting in an artificially high QoE if the vendor is not, in fact, doing what he was paid to do, thus rating low in QoS.
In medical terminology QoE is also known as "Quality of Patient Experience," and is a subjective measure of a patient's experiences with a medical practice. It looks at a care provider's offering from the standpoint of the patient's holistic experience, and asks, "How did patient fare after the treatment was concluded over an extended period of time? Did they enjoy a higher, similar, or lower quality of life after the treatment? For how long? How did this patient's quality of life, post-treatment compare with other patients who received similar treatment" And then asks, "What changes need to be made to the treatment to enhance the patient's quality of life?"
QoE in the context of telecommunications networks (here more recently also abbreviated as QoX) is a purely subjective measure from the user’s perspective of the overall value of the service provided. Apart from its being user dependent, it will invariably be influenced by the user’s terminal device (for example Low Definition or High Definition TV), his environment (in the car or at home), his expectations (cellular or corded telephone), the nature of the content and its importance (a simple yes/no message or an orchestral concert). Mean Opinion Score (MOS) used for assessing the quality of telephone connections is a limited form of QoE measurement process, relating to a specific media type, in a controlled environment and without specific user expectations. MOS has been expanded to assess the quality of television over ADSL (IPTV), by judging jittering, blockiness and artefacts of a viewed video signal.
Although QoE is perceived as subjective, it is the only measure that counts for customers of a service. Being able to measure it in a controlled manner helps operators understand what may be wrong with their services. "The only way to know how customers see your business is to look at it through their eyes." Daniel R. Scoggin
[edit] Quality of Experience in Engineering Processes
As an important measure of the end-to-end performance at the services level from the user's perspective the QoE is an important metric for the design of systems and engineering processes. This is particularly relevant for video services because bad network performance may highly affect the user's experience, mainly due to the fact that these services are compressed and have low entropy. So, when designing systems the expected output, i.e. the expected QoE, is often taken into account also as a system output metric. This QoE metric is often measured at the end devices and can conceptually be seen as the remaining quality after the distortion introduced during the preparation of the content and the delivery through the network until it reaches the decoder at the end device. There are several elements in the video preparation and delivery chain and some of them may introduce distortion. This causes the degradation of the content and several elements in this chain can be considered as "QoE relevant" for video services. These are the encoding system, transport network, access network, home network and end device.
