Abstract: A computing device receives an indication of a selected category of items relating to call quality for a plurality of voice calls, such as sites, wireless network identifiers, driver software versions, client software versions, protocols (e.g., virtual private network (VPN), Transmission Control Protocol (TCP), and User Datagram Protocol (UDP)), connectivity methods, and edge servers used in the calls. The computing device selects items in the selected category based on volume of calls. The computing device calculates percentages of poor calls associated with the items, and identifies high-volume poor call items. The computing device also may calculate impact ranks for categories of items, e.g., based on distribution of poor calls, with a lower rank being assigned if poor calls are evenly distributed, and a higher rank being assigned if a small number of items contribute disproportionately to the volume of poor calls.