Cross-training decisions in field services with three job types and server-job mismatch

To be cost-effective, field service managers must balance the high cost of machine downtime with the high cost of cross-training technicians in multiple skills. We study a field service system with three job types requiring three different skills. Each server has a primary skill, the cost of which is considered sunk, and up to two secondary skills, which is a managerial decision. We model two important characteristics that distinguish field services: server-job mismatch and the ratio of travel time to service time. We use a queueing framework and simulation to study three cross-training decisions: the number of servers cross-trained in secondary skills, the number of secondary skills each server should have, and the efficiency in each secondary skill. We find that complete cross-training is cost-effective in some field service situations. Typically, efficiency in secondary skills must be close to 100%, but when the probability of mismatch is high and the ratio of travel time to service time is high, efficiency in secondary skills must be less than 100%.