A SIPOC Diagram summarizes Suppliers, Inputs, Process, Outputs, and Customers so teams can align on process scope before detailed analysis.
Definition
A SIPOC Diagram is a high-level process map that identifies Suppliers, Inputs, Process, Outputs, and Customers. It is used to frame a process before detailed mapping, measurement, or root cause analysis.
The tool is deliberately simple. Its value is alignment around boundaries, customers, outputs, and required inputs.
History
SIPOC became a standard Six Sigma Define-phase tool because DMAIC projects often fail when the process scope and customer requirements are unclear. It also reflects supplier-input-process-output-customer thinking from systems and quality management.
When to Use
Use a SIPOC Diagram at the start of an improvement project, when teams disagree about boundaries, when handoffs are unclear, or before building detailed maps, data collection plans, or CTQ trees.
Step-by-Step
- Define the process name, start point, and end point.
- List five to seven major process steps.
- Identify key outputs from the process.
- Identify customers who receive those outputs.
- Identify inputs needed to perform the process.
- Identify suppliers of those inputs.
- Review scope, assumptions, and missing stakeholders.
- Use the SIPOC to guide CTQs, metrics, and detailed mapping.
Examples
- Manufacturing: Raw material supplier, incoming material, production process, finished part, and assembly customer.
- Service: Customer request, required information, review process, approved response, and customer.
- Healthcare: Referral, patient data, scheduling process, appointment, and patient/provider customer groups.
Common Pitfalls
- Adding too many process steps.
- Confusing inputs with process actions.
- Missing internal customers.
- No connection to CTQs or data collection.
- Using SIPOC as a detailed flowchart.
- Failing to validate with people who do the work.