Asking What—When—Where—Why—Who—How… and Then Some… for the Toyota Practical Problem Solving

The Toyota Practical Problem Solving is a very structured approach to solve problems. The underlying PDCA is broken down into multiple steps, where the “Plan” part especially is divided into Clarify the Problem, Break Down the Problem, Set a Target, and a Root-Cause Analysis. In this post I will look at the What—When—Where—Why—Who—How structure, also known as the 5W1H,  that can help you when clarifying the problem. This structure was used in journalism starting around 1913, but may originate from Greek antiquity. It is also a useful structure for problem solving.

Introduction to the Toyota Practical Problem Solving

The Toyota Practical Problem Solving consists of the steps listed below. In their entirety, they are also the PDCA (Plan, Do, Check, and Act). Toyota commonly uses the A3 format to put the problem solving on a single sheet of paper.

• Clarify the Problem
• Break Down the Problem
• Set a Target
• Root-Cause Analysis
• Develop Countermeasures and Implement
• Monitor Process and Results
• Standardize and Share

I have written extensively on the Toyota Practical Problem Solving. The first post of this longer series is the Introduction. In this post, I will focus on stratifying or clarifying the problem, which is one major subsection of the “Plan” part. Keep in mind that for Toyota, the “Plan” is by far the largest and most important part of the PDCA, as shown below.

What Do We Want to Achieve with the Stratification?

The practical problem solving is best suited for medium-complex problems. If it is a very small problem, then you should just do it. If it is a very large problem (e.g., designing a new plant), a simple A3 is not going to cut it, and you will need a larger team with more documentation. But for medium-sized problems you may have a number of possible root causes that could affect your problem.

The stratification looks at the available information (data, shop floor feedback, experiments) from multiple angles to determine which factor has how much influence on your problem.

What—When—Where—Why—Who—How

The “What—When—Where—Why—Who—How” method is a fundamental and intuitive framework for gaining a comprehensive understanding of a problem, situation, or event. It’s often one of the first analytical tools people instinctively use because it helps to quickly establish the core facts and parameters. Here are a number of possible questions that could be asked for each step. Keep in mind that there is often more than one possible question that could—and should—be asked for each of the “What—When—Where—Why—Who—How.” Also note that not every possible question must start with the leading word of that section.

“What” focuses on defining the problem itself:

• What exactly is the problem or event? Can it be precisely described?
• What are the symptoms or manifestations of the problem?
• What are the observable facts or data related to the problem?
• What is the impact or consequence of the problem?
• What is not happening that should be happening?
• What changes have occurred that indicate a problem?
• What are the measurable aspects of the problem?

“When” focuses on the timing of the problem:

• When did the problem first occur?
• When does it typically occur? (e.g., always, only on certain days, at specific times of day)
• When did it last occur?
• What is the frequency of the problem? (e.g., hourly, daily, weekly, intermittently)
• Is there a specific sequence of events leading up to the problem?
• Does the problem occur during certain shifts, seasons, or periods (e.g., end of month, holidays)?
• When does the problem not occur, even when conditions seem similar?

“Where” focuses on the location, but also often to the product (i.e., which product is it happening to):

• Where exactly does the problem occur? (e.g., specific machine, department, floor, geographic region, software module)
• Where does it not occur, even in similar environments?
• Is it confined to a specific area or does it spread?
• What are the environmental conditions in the location? (e.g., temperature, humidity, noise level, digital environment)
• Is the problem associated with a particular workstation, piece of equipment, or network segment?

The question “Why” is already famous from the “5 Why“, which is used to drill down to the root cause. However, with some care it can also be used to understand the different directions of the problem, albeit its larger use is indeed for the root cause analysis.

• Why is this process designed this way?
• Why are people behaving in this manner?

“Who” looks at the people involved. In this section make sure you do not blame people, but rather understand what leads to people possibly making mistakes (e.g., a lack of training)

• Who is experiencing the problem? (e.g., customers, employees, specific user groups)
• Who is involved when the problem occurs? (e.g., specific operators, teams, shifts)
• Who is affected by the problem?
• Who should be involved but isn’t?
• Who could potentially provide information about the problem?
• Are there specific skill sets, training levels, or behavioral patterns associated with the problem

“How” dives deeper in the process or mechanism:

• How did the problem happen? What was the sequence of events?
• How is the process currently executed? What are the steps?
• How do current procedures contribute to or fail to prevent the problem?
• How is the system/machine/process supposed to work, and how does it deviate?
• How are resources (time, money, materials) being used or misused?
• How does the problem manifest itself? (e.g., slowly, suddenly, with warning signs)

More Questions?

While this “What—When—Where—How—Who” is the most common approach, you can easily expand this with additional questions. For example, if you haven’t used it already during the “Where” section, “Which” is used to narrow the problem down:

• Which specific component, item, or individual is involved (out of a group)?
• Which factors are most significant or contributing most to the problem?
• Which part of the process is failing?
• Which external influences are most relevant?

Another possible question goes into the direction of “How Much” or “How Many” to understand the scale, frequency, cost, or impact in numerical terms:

• How much does this problem cost? (in time, money, resources, lost sales)
• How many units/incidents are affected?
• How much time is lost due to this problem?
• How many resources are consumed or wasted?

And finally, you could ask “For Whom” to understand the involved parties (this may also see less use than the questions above):

• For whom is this problem most critical?
• For whom are we trying to solve this problem? (Who are the end users, customers, or internal beneficiaries?)
• For whom are the current processes inefficient or painful?

Summary

Overall, this “What—When—Where—Why—Who—How”… and maybe also “Which—How Much/How Many—For Whom” can help you to look at the problem from different angles. Of course, not all questions make sense for every problem. If one of the many questions above look valid, ask them and try to get the answer through data or observations. If a question does not make sense at all for your situation, skip it. Again, the idea is to narrow down and understand the problem in more detail, not just to put check marks next to a list of generic questions. Now, go out, ask yourself What—When—Where—How—Who… and maybe also Which—How Much/How Many—For Whom, and organize your industry!