Plan-Do-Check-Act (PDCA) Cycle

PDCA ("Plan-Do-Check-Act") is an iterative four-step problem-solving process typically used in business process improvement. It is also known as the Deming Cycle, Shewhart cycle, Deming Wheel, or Plan-Do-Study-Act.

PLAN

• Establish the objectives and processes necessary to deliver results in accordance with the expected output
• Make the expected output the focus
• Align Plans to business outcomes
• Design processes with Business Effectiveness, Efficiency and Economy in mind

DO

• Implement the new processes
• Manage the new processes to ensure that they are working according to the Plan
• Note: The Plan may be faulty!

CHECK (STUDY)

• Measure the new processes
• Compare the results against the expected results with industry or corporate norms
• Determine any differences
• Analyze the differences using statistical methods
• Identify potential Problems

ACT

• Identify the Problem
• Establish the probable Root Cause(s) to the Problem
• Investigate and Diagnose the Root Cause
• Determine the Solution(s) for the Root Cause
• Evaluate the "best" feasible Solution to resolve the Problem

The concept of PDCA comes out of the Scientific Method, as developed from the work of Francis Bacon.

Shewhart described manufacturing under "control" - under statistical control - as a three step process of specification, production, and inspection. Shewhart says that the statistician "must help to change the demand [for goods] by showing...how to close up the tolerance range and to improve the quality of goods."

Deming shortened the steps to the now traditional Plan, Do, Check, Act. Deming preferred Plan, Do, Study, Act because 'Study' has connotations in English closer to Shewhart's intent than "Check."