Operations Research (OR) is one of those fields that is being constantly being placed in different departments. For example, at my university, it’s a branch of industrial engineering. In business school, it’s under data science and business intelligence. In some other universities, it’s under the computer science department. Even the name changes. It is called decision science, operations management, mathematical optimization and operations research. But none of these convey the real purpose of the field.

Here’s a few descriptions, explained as if the audience was 5, 20, as an undergraduate and a graduate student:

ELI5: Operations research is a way of using math and computer science to help people and businesses make better decisions.

ELI20: Operations research is a field that uses mathematical and analytical techniques to help make better decisions in areas such as business, engineering, and the military. It involves using computers to solve complex problems and make predictions about the future.

ELIUndergrad: Operations research is a discipline that focuses on the use of advanced analytical and mathematical techniques to help make better decisions in complex situations. It is often used in fields such as business, engineering, and the military, and involves the use of computers to solve problems and make predictions. Operations research analysts use a variety of methods, such as optimization, simulation, and statistical analysis, to help organizations make better decisions and improve their operations.

ELIGrad: Operations research is a branch of mathematics that deals with the optimization of complex systems. It is concerned with the development and use of mathematical models and techniques for the design, analysis, and improvement of systems and processes. Operations research has a wide range of applications, including in fields such as business, engineering, and the military. It involves the use of advanced analytical and mathematical tools, such as optimization algorithms, simulation models, and statistical analysis, to help organizations make better decisions and improve their operations.

My own explanation: It is a way to model a cyber-physical system, such as a production plant, a supply chain, an airline scheduling system or a layout of a hospital, in order to produce a Digital Twin. The model in itself is a set of mathematical equations that represents the systems decisions, constraints and objectives, which in turn can be used to compute a set of best decisions to take within the defined constraints to obtain a feasible or optimal objective. For example, maximizing truck utilization, minimizing waste, maximizing production throughput, or even a mix of objectives, such as minimizing overtime and maximizing resource utilization.

My professor and advisor once explained OR with this great analogy:

Business planners (think production planners or schedule makers) are like arc-bridge builders. They are constantly trying to plan how to make a bridge but most of the time a straight bridge is quick and adequate enough to get by for them. On the long run, the bridge is not sturdy enough and has to be reworked, so more time is passed on the bridge design and rebuilding. OR is a method that instantly gives you the keystone piece of your bridge to make it robust, efficient and an army of planners would take months to come by.