Abstract: A method for assessing the quality of service of telephone calls on a trunk includes identifying and counting telephone call sequences including a plurality of telephone calls placed on the trunk. Each of the telephone calls in the sequence has the same originating telephone number and the same destination telephone number and a start time and a stop time and an elapsed time between the stop time of a telephone call and the start time of the next telephone call in a sequence being less than a predetermined amount. Identifying and counting unanswered reattempted telephone calls or answered reattempted telephone calls. A ratio is calculated between the number of identified unanswered or answered reattempted telephone calls to the number of identified telephone call sequences, such that the ratio provides a measure of the quality of service of telephone calls on the trunk.