Kingman’s equation provides insights into the mean waiting time before a process. Machines usually have a queue before them, and John Kingman described how a queue forms mathematically in 1961. He did this for a single server. So, for a queue waiting for one process or machine. Kingman’s equation is an approximation of the mean waiting time.
Three elements influence the time spent in the queue:
1. Processing time of a job
2. Utilisation of the process/machine
3. Variation in the process or arrival of jobs
The principle behind Kingman’s equation to approximate the mean waiting time can be expressed as:
Mean waiting time = (Processing time of the Job) X (Effect of Utilisation of the Processes/Machinery) X (Effects of Variation)