A Queuing Model for Telephone Operator Staffing

In the Bell Telephone System, service criteria for telephone operator staffing are based on target delays. The goal is to ensure that customers receive good levels of service during normal load times and to protect against very poor service during peak load periods. The system's staffing problem cannot be solved using standard queuing models because of: 1. the large number of servers involved, 2. bimodal service time distributions, 3. nonstationarity of customer arrivals, 4. customer abandonment and reattempts for service, and 5. nonpreemptive priority rules for service. Therefore, a new queuing model was developed to generate staffing tables for each operating system and range of service times per customer. The tables specify the number of servers required to meet given load levels under average delay criteria, based on load forecasts derived from historical data, usage trends, and traffic growth patterns. The staffing tables are then used to arrange individual operators' schedules to meet service requirements per half hour.