Quality of experience (QoE) is a widely used term in the telecommunication industry. However@ there is no single document available that describes methods for assessing QoE. This Recommendation provides a reference guide to existing standardized methods in ITU for QoE assessment. The overall approaches for the different assessment methodologies typically used are described@ and a taxonomy of QoE assessment standards is defined. For different applications@ this Recommendation identifies suitable subjective assessment methodologies@ and where applicable@ objective assessment methods that can be used to estimate subjective opinion@ in addition to giving guidance on their usage and limitations. The intended users of this Recommendation include telecommunication carriers@ service providers and equipment manufacturers.