1. A dependability measurement system comprising; performance measurement means for measuring performance parameters between a first location and a second location in a communications network at sufficient frequency to detect service-affecting failures and time-of-occurrence; service-affecting event computation means for analyzing performance parameters measured by the performance measurement means; equipment event measurement means for monitoring network elements of the communications network for the occurrence of network element events; population calculator means for determining components within the communications network which are related to dependability metrics to be reported upon and calculating in-service time information for the components; dependability metric calculator means for calculating, analyzing and reporting dependability parameters and dependability metrics using information output from the service-affecting event computation means, equipment event measurement means and population calculator means; and a user interface for supplying the dependability measurement system with system parameters and control information wherein the dependability metric calculator means comprises information correlation means for correlating information from the service-affecting event computation means and the equipment event measurement means.