A system for analyzing the performance of a network includes a data collection agent that collects performance data including first and second sets of measurements of a single network parameter. First and second variance statistics are calculated. A user is alerted about potential network performance problems based on whether a predetermined relationship exists between the variance statistics. The user may be notified by sending an e-mail to the user; and/or sending a fax to the user; and/or initiating a phone call to the user. The user may be alerted by a message to a PDA or a cellular telephone.