SIPOC Diagram

A SIPOC diagram is a process improvement tool used in the Six Sigma methodology and Lean manufacturing. It is used to identify all relevant elements of a process before any improvement project begins. SIPOC diagrams are most beneficial when used in the “define” step of the DMAIC cycle, before beginning a Kaizen event, or as the first step to process mapping. It will ensure everyone has a mutual understanding of the process before decisions are made.

It’s a fairly straightforward diagram and should present all of the important process information in a clear, easy-to-understand way. Although simple, the SIPOC is a high-level took that identifies process boundaries, clearly defines customers and suppliers, and helps to identify what data needs to be collected to measure results. Creating a SIPOC table before embarking on a process improvement project can make all the difference.

There are a number of reasons for creating a SIPOC diagram depending on the audience. These tables can be used to give a high-level overview of a process people may be unfamiliar with, to refresh memories for those who no longer know the process, or to help people understand a new process. The diagram lays out a simple summary of the inputs and outputs of one or more processes in a table; even someone completely unfamiliar with a process will gain a clear understanding of the process at hand.

Completing a SIPOC Diagram

Each element makes up its own column on the SIPOC table and represents the process from beginning to end:

  • Suppliers: Who supplies the process inputs?
  • Inputs: What inputs are required?
  • Process: What are the major steps in the process?
  • Outputs: What are the process outputs?
  • Customers: Who receives the outputs?

Arguably the most important part of this diagram is clearly defining the inputs and the outputs of the process. These could be either internal or external and could represent materials, services, or information.

It should be noted that SIPOC diagrams are sometimes referred to as COPIS, standing for Customers, Outputs, Processes, Inputs, and Suppliers. The only difference is the emphasis on the value of the customer.


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