Quality of Telephone-Based Spoken Dialogue Systems is a systematic overview of assessment, evaluation, and prediction methods for the quality of services such as travel and touristic information, phone-directory and messaging, or telephone-banking services. A new taxonomy of quality-of-service is presented which serves as a tool for classifying assessment and evaluation methods, for planning and interpreting evaluation experiments, and for estimating quality. A broad overview of parameters and evaluation methods is given, both on a system-component level and for a fully integrated system. Three experimental investigations illustrate the relationships between system characteristics and perceived quality. The resulting information is needed in all phases of system specification, design,