Background

Four Types of Problems – Overview

Four Types of Problems, from the Lean Enterprise Institute, reveals how leaders can break the hammer-and-nail scenario by recognizing four main problem types to precisely apply the right problem-solving approach to the right problem

Lean thinking starts with the phrase “What problem are you trying to solve?” But is the true understanding of problem solving getting lost amongst the noise and confusion of the numerous methods and approaches used to go about “solving” the issues faced day to day?

There was a need to explain the various methods we can use to “solve” problems, all of which should incorporate Plan-Do-Check-Act to some degree.

Art Smalley, author of  Understanding A3 Thinking and Toyota Kaizen Methods did just that in his latest book – Four Types of Problems. 

However Art went one stage further by providing a taxonomy to the problems we encounter.

If we understand the types of problems, we stand a better chance of applying an appropriate process to “solving” them. Thus we avoid the issues in the famous quote from Abraham Maslow, “I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.”

Most business problems fall into four main categories (see the diagram below), each requiring different thought processes, improvement methods, and management cadences:

Before using a method to solve a problem you need to understand what type of problem you are trying to solve.

Troubleshooting: A reactive process of rapidly fixing abnormal conditions by returning things to immediately known standards. 


e.g. When you get a flat tyre change it.

Gap-from-standard: A structured problem-solving process that aims more at the root cause through problem definition, goal setting, analysis, countermeasure implementation, checks, standards, and follow-up activities.


e.g. When you find out suddenly you are getting flat tyres every week find out why.

Target-state: Continuous improvement that goes beyond existing levels of performance to achieve new and better standards or conditions.


e.g. Determine you are sick of getting flat tyres and look for a better tyre.

Open-ended and Innovation: Unrestricted pursuit through creativity and synthesis of a vision or ideal condition that entail radical improvements and unexpected products, processes, systems, or value for the customer beyond current levels.


e.g. Ask why not make tyres that run flat.

“Organisations and individuals at all levels fall into this trap of having one primary or standard way of solving every problem,” said Smalley, who learned problem solving at Toyota’s historic Kamigo engine plant from Harada-san.

Selecting Problem Solving Methods – Considerations

When selecting a problem solving method there are two main considerations to think about:-

  • Type of problem – Complexity and time to solve.
  • Density of problem – The Quantity and “Who” to solve them?

Before using a method to solve a problem you need to understand what type of problem you are trying to solve.

Use the 4 types as a guide and consider the amount of data & facts needed to be collected, analysed and time it could take to solve the problem.

As well as the Types of Problem, the “density” and “Who” should be solving the problem also need to be considered when selecting the right problem solving method.

A very few large complex problems in an organisation may need to be addressed by a selected skilled team and supported by a highly capable expert or leader.

A few medium size & medium complexity problems can be tackled directly by line managment with the support of selected team members / stakeholders.

Many small problems with less complexity would be better addressed quickly, directly by team members involved with the work.

The largest density of “many small problems” in an organisation are usually hidden from management. (As managers don’t directly do the work.)

A lot of organisations concentrate on the large or medium problems, as this is where the management are focused on a day to day level.

However some large and medium problems start off as small problems and escalate to large ones!

Everyone in an organisation needs to identify and contribute to solving the many small problems.

Problem Solving Methods

There are many different “scientific” problem solving methods available to consider, but it’s critical to try and select the most appropiate method for the type of problems and density of the problems you are trying to solve.

The visual framework below places the scientific problem solving methods into Four main levels: React, Rapid, Practical & Advanced

React – for types 1

React problem solving is not strictly “scientific” based problem solving, but more focused on “gemba” (at the place of work) fact based learning that is done rapidly through PDCA trial and error analysis.

Rapid Problem Solving – PDCA Scientific for Type 1, 2 & 3 problems:

  • Is a P-D-C-A approach using 4 to 3 steps, such as Quadrant Charts (or B.O.S), 3C’s – Concern Cause & Countermeasures.
  • Fast but structured approach to problems with simple data collection & analysis.
  • Uses the 7 Problem Solving tools to support (Pareto chart, Cause & Effect Fishbone, Graphs & Control Charts, Check Sheets, Histograms, Scatter diagrams, Stratification.)

Practical Problem Solving – PDCA Scientific for Type 2, 3 & 4 problems:

  • Is a 8 step approach developed by Toyota to provide more scientific structure to original PDCA.
  • Used for current and mid-term business issues requiring more analysis to get to the root causes and data collected to prove thinking.
  • Uses the 7 Problem Solving tools to support.
  • A3’s used to capture the story to confirm and share learning.

Advanced Problem Solving Scientific for types 2, 3 & 4 problems:

  • Are methods such as Six Sigma, Design for Six Sigma, Shainin (Statistical Engineering/ RED X), TRIZ (Theory of inventive Problem Solving.)
  • High level use of statistical and analytical tools to prove thinking – High level of capability needed.
  • Can be used for technical high complexity problems typically found in technical processes, design and engineering.

Now move onto the next Topic – Purpose