What is the "5W1H" phase section and how to use it?

Section: 5W1H

The 5W1H method is a fundamental tool in lean manufacturing, used for problem-solving, root cause analysis, and continuous improvement. It stands for What, Why, Who, When, Where, How.

It is a process of asking these 5 questions about a problem which in turns provides answers that help in understanding the problem and enabling us to solve it properly.

Let us understand this with a simple example where we take a problem and apply 5W1H to understand the working and eventually solving the problem:

The Problem: Defective products being produced.
Question 1	What	Definition	Identify the specific problem.
Example	There is an increase in defective products coming off the production line.
Question	What exactly is the problem?
Purpose	To ensure everyone understands the specific issue at hand.
Question 2	Why (Replaced by Which in Lean Suite)	Definition	Determine the reasons behind the problem.
Example	The defects might be due to a malfunctioning machine, incorrect material, or human error.
Question	The defects might be due to a malfunctioning machine, incorrect material, or human error.
Purpose	To dig deeper into the cause of the problem. Often, this involves asking "Why?" multiple times until the root cause is identified (the "5 Whys" technique).
Question 3	Who	Definition	Identify the people involved or affected.
Example	Operators on the production line, maintenance staff, quality control inspectors.
Question	Who is involved in this process? Who is affected by the problem?
Purpose	To determine who needs to be consulted, who can provide insights, and who will be responsible for addressing the issue.
Question 4	When	Definition	Establish the timing of the problem.
Example	The defects started occurring after a recent maintenance procedure or during a particular shift.
Question	When did the problem start? When does it occur?
Purpose	To identify patterns or specific times when the issue happens, which can help narrow down potential causes.
Question 5	Where	Definition	Locate where the problem is happening.
Example	The defects are occurring at a specific station on the production line.
Question	Where are the defective products being produced?
Purpose	To pinpoint the exact location of the issue, which can be crucial for identifying the cause.
Question 6	How	Definition	Understand how the problem occurs.
Example	The defect happens during a specific stage of production, perhaps when a particular machine is used.
Question	How are the defects being produced? How is the process carried out?
Purpose	To understand the process details and identify any deviations or issues in the procedure.
An example of how the answers might help to solve the problem
What	Defective products are being produced.
Why (Replaced by Which in Lean Suite)	The defects are due to a misalignment in the machine that wasn't detected during routine checks.
Who	The operators, maintenance team, and quality control inspectors are involved.
When	The issue started after a recent maintenance procedure and is particularly noticeable during the night shift.
Where	The defects occur at the third station on the production line
How	The misalignment happens during the third stage of production when the machine applies a specific process incorrectly.