or coded and presented in either tabular or graphic formats as a user selected option. Displays may show real-time status as well as historical information. Groupings Any one supervisor may typically be responsible for 10-15 agents, even though the entire group serving a particular func- tion may be much larger. Supervisors may be able to identify agent information for their specific agents without scrolling through the entire group display. Similarly, supervisors may be able to display a subset of agents from several different groups, if necessary (for example, in evaluating trainees throughout the Call Center). This super group/ sub group capability is very im- portant in larger Call Centers. Reports In addition to real time information used for daily supervi- sory functions, historical reports are necessary. These identify trends and are vital to planning. Reports may include information about individual agent and group performance, trunk usage, transaction codes, emergency recording and alerts. In addition to standard reports, systems may permit supervisors or administrators to develop custom reports, unique to their own Call Center requirements. Raw data is stored for some management-defined period of time, and is available for additional reports for a period of at least a week, up to one or more years. The Telecom Handbook 30 85 THE ACD Monitoring Displays and reports tell only part of the story of agent per- formance. To really evaluate agent performance and to assess the quality of service provided, supervisors must be able to listen to agents in actual telephone conversation with callers. This has traditionally been accompanied by a supervisor walking to the agent's desk and listening to the call by plugging a second head- set into the station set. This approach has become an accepted part of Call Center culture for many organizations. However, the same result can be achieved with silent and split/silent monitor. Silent monitor allows the supervisor to listen, undetected, to both the agent and the caller