Chapter 2 – Operations management (McGraw-Hill Cachon & Terwiesch)

Process
A set of activities that make a collection of inputs, perform some work for activities with those inputs, and then yield a set of outputs
Process flow diagram
A graphical way to describe the process. It uses boxes to depict resources, arrows to depict flow, and triangles to depict inventory locations.
Resource
A group of people and/or equipment that transforms inputs into outputs
Process scope
The set of activities and processes included in the process
Flow unit
The unit of analysis that we consider in a process analysis; for example, patients in a hospital, scooters in a kick scooter plant, and calls in a call center
Process metric
Scale or measurement of process performance and capability
Inventory = I
The number of flow units within the process
Flow rate = R
The rate at which flow units travel through a process
Flow time = T
The time of flow unit spends in a process, from start to finish
Little’s law
The law that describes the relationship between three key process metrics: inventory, flow rate, and flow time.
Little’s law equation
Inventory equals flow rate multiplied by flow time. I = RxT
Flow rate equation
Flow rate equals inventory divided by flow time. R = I/T
Flow time equation
Flow time equals inventory divided by flow rate. T = I/R