Ed Kaplan on the 50th Anniversary of Little's Law

Edward H. Kaplan, the William N. and Marie A. Beach Professor of Management Sciences, Professor of Public Health, and Professor of Engineering, was one of four scholars invited by the editors of Operations Research to comment on the importance of Little's Law on its 50th anniversary. Little's Law, which is taught to SOM students in the Operations Engine core course and in the Policy Modeling elective, is arguably the most influential formula in queuing theory. Published by John Little in 1961, it proves that the average number of items in a queuing system equals the average arrival rate of items to the system, multiplied by the average waiting time of an item in the system.

In his commentary, "It May be Little But It's the Law!" Kaplan describes how Little's Law applies not only to issues in operations management, but to problems in epidemiology and public health, stocks and flows, and counterterrorism. Kaplan writes, "…[O]ne of the most exciting things about operations research is that with a little (!) effort, one can find operations everywhere, enabling the application of our modeling mindset to create relevant operations models for whatever problem is of interest. Little's Law is a key piece of the 'sophisticated common sense' that comprises our operations research toolkit, and so it shall remain."

Read the commentary.