Abstract: A system identifies calling parties who are unable to successfully complete calls to a called party. Call attempt failure records are retrieved from a local exchange carrier that services the calling parties, from a local exchange carrier that services the called party, and from an interexchange carrier that carries calls between the two local exchanges. Call completion records are retrieved from the local exchange carrier serving the called party. The failure records are compared to the completion records to determine which calling parties experienced one or more failed call attempt to the called party, and of these calling parties, which parties also failed to complete subsequent call attempts to the called party. The system also reports the intensity of calls made by these parties to the called party over a specified time period.