Comparison of problem-solving methods and techniques

Methods and techniques for problem solving

Problem-solving is an essential skill in everyday life, in the professional world, and even in scientific research. However, with the multitude of approaches, methods, and techniques available, it can be challenging to navigate. Each problem is unique and may require a different approach. We will attempt to clarify the landscape of these approaches and methods by explaining their primary differences and when to use them, all summarized in the image above.


1 Comprehensive Problem-Solving approaches

This category encompasses complete and structured methods for tackling problem-solving in a systematic way. These approaches are designed to guide individuals or teams throughout the problem-solving process, providing clear and ordered steps to follow.



The DMAIC approach is a structured problem-solving method, divided into five main steps:

  1. Define : Identify the problem, set objectives, and define the scope of analysis.
  2. Measure : Gather data to assess the current performance of the process and measure variability.
  3. Analyze : Dive deep into the data to identify the root causes of the problem.
  4. Improve : Develop and implement solutions to eliminate the identified problem causes.
  5. Control : Establish control mechanisms to monitor results and maintain long-term improvements.


Distinctiveness from other comprehensive problem-solving approaches:

The DMAIC approach stems from the Six-Sigma philosophy and places a greater emphasis than other global methods on quantified data, through measurement, and quantitative statistical analyses.


Preferred application

DMAIC is suitable for any type of recurring problem-solving, from medium to high complexity, occurring in an organization's processes or operations. Especially for problems that require quantitative data analyses.



1.2 8D Method

The 8D method is a structured problem-solving approach which stands for "eight disciplines" summarized as follows:

  1. Form a multidisciplinary team: Create a problem-solving team composed of people with diverse skills.
  2. Define the problem: Clearly identify the problem, its scope, and the resolution objectives.
  3. Implement immediate measures: If necessary, take emergency actions to contain the problem.
  4. Identify causes: Pinpoint the root causes of the problem.
  5. Develop corrective actions: Design corrective actions to eliminate the immediate causes.
  6. Implement corrective actions: Execute the corrective actions and monitor their effectiveness.
  7. Prevent recurrence: Validate that corrective actions are effective and prevent the problem's recurrence.
  8. Acknowledge the involved individuals: Document the resolution process and recognize the team's contributions.


Distinctiveness from other comprehensive problem-solving approaches:

It explicitly introduces a step to implement immediate actions before identifying the root causes.


Preferred application

Even though the method applies to recurring problem-solving, from medium to high complexity, it tends to be mainly used for medium complexity problems that require urgent actions.


1.3 The A3 method

The A3 method originates from the Toyota Production System (TPS). At Toyota, the A3 paper format was adopted to document, visualize, and share problems, analyses, and solutions concisely. This format has become a principle for reporting, and particularly applied in problem solving. It is more a principle than a method. The steps in the A3 method are not specified, but often follow the example below:

  1. Describe the current situation
  2. Define the objective
  3. Identify the root causes
  4. Define the corrective actions
  5. Define the implementation plan
  6. Track the results
  7. Learn from the experience


Distinctiveness from other comprehensive problem-solving approaches:

It emphasizes clarity of communication through a simple, visual document containing concise information.


Preferred application

Although the method applies to recurring problem-solving, from medium to high complexity, it tends to be primarily used for medium complexity problems.


1.4 The Change or Transformation project

The Transformation, or Change approach, is a comprehensive method for solving complex problems related to an organization and its operational methods (organization, governance, management methods, processes, staff skills, and motivations...). It involves conducting an in-depth diagnostic of the organization to identify its strengths, weaknesses, opportunities, and threats, then using this information to draft a transformation or improvement plan which will involve a significant part of change management. This approach relies on a holistic analysis of the current company situation, followed by designing and implementing a project aiming to achieve specific change or improvement goals. 

Distinctiveness from other comprehensive problem-solving approaches:

There isn't truly a Change/Transformation approach that has established its "brand", acronyms, and standard structure like DMAIC, 8D, etc. However, all Transformation projects apply similar approaches, and they are frequent enough that this approach deserves to be on our list.
It places a more particular emphasis on organizational, managerial, and human aspects, even though process improvement is also part of its scope.

Preferred application

This method mainly applies to solving recurring problems of high complexity of organizational and human nature (organization, governance, management, skills, and motivation...) especially across multiple departments or services of the organization.


1.5 The PDCA method

The PDCA (Plan, Do, Check, Act) is a continuous improvement cycle used to solve problems, enhance processes, and achieve goals. Here's a brief description of each step:

  1. Plan: Identify the problem or the objective, set goals, design an action plan, and choose methods to achieve them.
  2. Do: Implement the action plan by executing the planned activities.
  3. Check: Evaluate the results obtained against the set objectives, by collecting data and checking performance.
  4. Act: Take measures to adjust, correct, and improve the plan based on the results of the evaluation. Repeat the cycle to continue improvement.


Distinguishing feature compared to other global problem-solving approaches:

PDCA is more of a continuous improvement principle based on a cycle that continually repeats to solve problems, enhance processes, or achieve objectives. It is more generic and can be applied to various situations.

Preferred application

PDCA is often used for incremental improvements and regular adjustments in a process or activity. It is less used to solve complex, identified, or chronic problems and to bring about significant improvements.


1.6 Kaizen

The Kaizen event, often referred to as "Kaizen Blitz" or simply "Kaizen," stemming from Toyota's production philosophy, is a targeted and intensive approach aimed at rapidly improving a process, product, or service within an organization.

It typically lasts from a few days to a week, brings together a multidisciplinary team, and follows a procedure of analysis, ideation, rapid implementation, and review.


Distinguishing feature compared to other global problem-solving approaches:

Although Kaizen covers the entire problem-solving process, it is more focused, both in terms of duration (a few days) and scope compared to broader approaches.

Preferred application

It is particularly suitable for low or medium complexity problems, aiming to achieve immediate and visible improvements, often focused on process efficiency and waste reduction, within a continuous improvement context.


1.7 Conclusion on global problem-solving approaches

These methods are quite similar, as they all rely on the clear identification of the problem, cause analysis, definition and implementation of actions, and monitoring of actions.

Except for Kaizen, which is more targeted than the others, the differences lie mainly in certain aspects more or less highlighted by one method or another.

The effectiveness of the method used will probably depend more on the way (rigor, demand, flexibility, commitment of individuals, etc.) it is implemented than the method itself.


2 Specific methods used within the problem-solving process

This category encompasses methods that are designed primarily for use in problem-solving, even though they can also be employed in other contexts. The methods in this category don't cover the entire process but are used within the process, at one or more of its stages.

2.1 5W2H Method

The method is a management and organization tool used to ask essential questions in order to gather specific and relevant information on a given subject. The letters 5W2H represent the initials of each question  as follows:

  1. What?: This question aims to clearly define the object or subject under examination. It's the first step to ensure everyone understands what's being discussed.
  2. Who?: This pertains to determining who is involved or affected by the subject. This could include individuals, teams, departments, or other stakeholders.
  3. Where?: This question seeks to identify places or locations related to the subject. This could mean physical locations, specific departments in an organization, or even geographical areas.
  4. When?: It's essential to determine the timeline or time frame associated with the subject. This can include deadlines, due dates, specific moments, and so on.
  5. Why?: The "Why?" question seeks to comprehend the motivations, reasons, or objectives behind the subject. It helps explore the reasons leading to a particular situation or decision.
  6. How?: This question delves into the methods, processes, or means used concerning the subject. It aids in understanding the steps or actions required to achieve a goal.
  7. How much?: This involves quantifying elements related to the subject. This can comprise figures, measurements, financial resources, quantities, and more.

The most appropriate use of the 5W2H method is typically in the Problem Definition phase for the following reasons:

  • Clarifying the subject: The "What?" question helps to precisely define what the project is about, avoiding ambiguity.
  • Identifying stakeholders: By answering the "Who?" question, the team can determine who's involved in the process or problem to be solved, which is vital for stakeholder management.
  • Location: The "Where?" question helps identify the physical places or areas of the organization affected by the project.
  • Scheduling: By answering the "When?" question, timelines and deadlines for the project can be set.
  • Understanding methods and resources: The "How?" and "How much?" questions help understand existing processes, available resources, and measurements related to the problem.
  • Understanding motivations: Finally, the "Why?" question can assist in grasping why the problem is crucial to solve.

2.2 Ishikawa method for identifying root causes

The Ishikawa diagram, also known as the fishbone diagram, is a problem-solving technique used to identify and analyze the root causes of a specific issue. It was developed by Japanese statistician Kaoru Ishikawa. Here's how it works:

  1. Problem identification: The team clearly identifies the problem or adverse effect that needs resolving. This issue is typically written at the far right of a fish-shaped diagram.
  2. Diagram creation: A fish-shaped diagram is drawn with a horizontal line representing the problem to solve. This line resembles a fish's spine.
  3. Cause categories: On the diagram, "spines" are drawn perpendicular to the central spine of the fish. These represent different cause categories that might contribute to the problem. Common categories include the "5 M's" (Material, Manpower, Methods, Environment, Machines) or the "4 P's" (Product, Processes, People, Partners).
  4. Identifying potential causes: The team then contemplates potential causes for each category and notes them along the corresponding spines. These causes are often identified through brainstorming sessions.
  5. Analyze and identify root causes: Once all potential causes are recognized, the team analyzes each to determine if it's genuinely linked to the problem and if there are deeper underlying reasons, in order to pinpoint the root causes. Techniques like Pareto charts, data analysis, or the "5 whys" can be employed to identify and prioritize causes based on their significance.

One can argue that the essence of the Ishikawa method lies mainly within stages 1 to 4, up to the identification of potential causes.

Step 5 is more an extension of the Ishikawa method involving the use of other data analysis methods, such as Pareto charts, statistical analyses, or other in-depth investigative techniques.

The Ishikawa method is suitable for two phases of the problem-solving process:

  • Problem Definition: The "core" of the Ishikawa method is apt as it allows for the identification of potential causes to clarify the problem's scope and the extent of subsequent analyses. Indeed, the analysis and identification of root causes stage is lengthier and more resource-intensive and will thus be more suitable for the next phase.
  • Identifying causes: Both the core of the method and its extension to other methods are used here. The strength of the Ishikawa method is its ability to identify and structure analysis axes using complementary approaches. It's also common to undertake the "core" of the method in the problem definition phase and continue it in this stage (after validating the continuation of the problem-solving process).

2.3 Process mapping and critique

If problem solving is oriented towards improving a process, then the method of process mapping is suitable. This method aims to understand, analyze, and improve a process by visualizing it in detail and identifying optimization opportunities. Within this framework, this method can be applied at two stages of the problem-solving process:

  • Problem definition: At this stage, a high-level map will be preferred, for example, a simplified flow diagram, such as a SIPOC. This is generally sufficient to identify the main opportunities to explore later and to clarify the problem definition.
  • Cause identification: In this case, and especially for complex problems or significant processes, a detailed mapping that includes all steps, subprocesses, tasks, and interactions will be favored. This can be complemented by a SIPOC map if major issues are identified concerning the documents used (inputs, outputs) and the providers or customers of these documents.

2.4 Structured questionnaires

Questionnaires are generally categorized under general techniques of the following chapter. However, since we are referring here to two very specific types of questionnaires designed for problem-solving, we place them in this category.

  • Scoping - Survey: A structured but simple questionnaire (some open questions and performance perception scores) is answered by a selection of organization leaders (scoping) or by a large number of employees (survey).
  • Assessment against a benchmark: A very precise questionnaire answered by a selection of leaders or experts to assess how certain practices are conducted and if they match the state of the art (the benchmark).

These two types of questionnaires are used in two different phases:

  • Scoping - survey is appropriate in the problem definition phase
  • Assessment against a benchmark is used in the root cause identification phase

2.5 Benefit/Ease Matrix

The Benefit/Ease matrix is a tool that allows for the evaluation and ranking of potential actions based on two key criteria:

  • Benefit: Benefits, whether qualitative or quantitative, expected from the implementation of each action.
  • Ease: This represents the ease with which the proposed actions can be implemented or carried out. Ease depends on various factors such as available resources, required skills, legal constraints, or local conditions.

This matrix helps prioritize actions by identifying those that are both significant in terms of issues and feasible in light of accessibility constraints. This approach enables the maximization of the impact of limited resources by focusing efforts on actions that are the most beneficial and achievable.

3 General techniques used in problem-solving

This category includes methods that are not specifically designed for use in problem-solving, but can be. They can also be more of techniques or principles rather than actual methods. Therefore, they can be integrated or used with more specific methods. For example, the "5 whys" can be used in the Ishikawa method to delve deeper into the causes indicated on each fishbone.

3.1 Brainstorming

Brainstorming is a technique for generating ideas creatively and collaboratively. It aims to gather a group of people to explore ideas, solutions, or concepts by encouraging free thought, creativity, and diversity of perspectives.

It is mainly used in the phases of:

  • Problem definition: Brainstorming can be used to gather initial ideas about areas that deserve particular attention, identify problems or opportunities requiring improvement.
  • Action definition: Brainstorming is particularly useful in this phase as it promotes the generation of a wide range of potential solutions to identified problems. It allows the team to think creatively about process changes, improvements, and innovations that could effectively solve the problems.

3.2 The 5 whys

The "5 Whys" is more of a technique than a method. It involves repeatedly asking the question "Why?" typically until the root cause of a problem is reached. The goal is to move beyond the obvious symptoms of a problem to identify underlying factors contributing to its occurrence.

3.3 Affinity diagram

The affinity diagram method, also known as the KJ method, is a group management technique used to organize and group ideas, information, or problems into logical categories. It consists of collecting items related to a subject, displaying them randomly, and then grouping them based on similarities or relations.

3.4 Quantitative data analysis

Data analysis is an essential element of problem-solving. However, the level of analysis, especially when it comes to quantitative analysis, varies greatly. Thus, we propose a categorization of analysis methods by complexity level to better indicate which analyses to use and when.

3.4.1 Categorization of analyses

Here is a categorization from the simplest to the most complex, with illustrations for each type, for quantitative analyses:

  • Descriptive Analysis: Summarizes and characterizes data.
    • Basic statistics (mean, median, mode, variance, standard deviation)
    • Graphs (bar charts, histograms, pie charts)
    • Pareto charts
  • Exploratory Analysis: Identifies trends, relationships, and patterns without having formal hypotheses.
    • Boxplots
    • Scatter plots
    • Correlation analyses
  • Inferential and Predictive Analysis: Makes predictions, inferences, or hypotheses about a population based on a sample, or uses existing data to predict future events.
    • Hypothesis tests (t-test, ANOVA)
    • Confidence intervals
    • Linear and logistic regression
    • Decision trees and random forests
    • Simple simulation
  • Prescriptive and Advanced Analysis: Suggests actions based on data, exploits complex information, or uses advanced techniques for analysis and prediction.
    • Optimization (linear programming, network optimization)
    • Simulation
    • Neural networks
    • Clustering (like K-means)
    • Deep learning techniques

3.4.2 When to use them during problem-solving?

It depends both on the stage and on the complexity of identifying the real root causes, especially through a quantitative analysis.

  • Problem definition phase: Generally, descriptive analyses are sufficient at this stage.
  • Cause identification phase: Descriptive analyses are naturally used. Exploratory analyses, and even inferential/predictive analyses, are often used for specific causes. For instance, when calculating the capability of a process and verifying that it meets requirements (such as the defect rate, non-quality rate, etc.). This is even the basis of the approach and the term "six sigma", which requires less than 3.4 defects per million. For very specific and complex problems, advanced methods (simulations, AI) may be used.
  • Action definition phase: The main data analysis performed here is estimating the impacts of the actions, which is usually a descriptive analysis. However, it may happen that you simulate and compare several scenarios by performing sensitivity analyses, exploratory, or even predictive types. It is also likely that with the maturation of AI-based techniques, these tools will be used more and more to make action recommendations.

3.5 The Business Case

In the context of problem-solving, the "Business Case" identifies the gains, costs, investments, and financial risks associated with solving the problem. It supports several actions, such as deciding to continue the problem-solving process, prioritizing causes and actions, or tracking results:

  • Problem definition: At this stage, the Business Case is used to decide whether to proceed with the analysis and action definition phases. The Business Case is generally vague at this stage due to a lack of many data.
  • Cause identification: An estimated quantitative impact of the different causes can help focus on the causes generating the greatest financial losses.
  • Action definition: The Business Case is established at the end of the phase to decide whether or not to implement the actions. This time it is more precise because all the necessary data could be collected in the previous phases.
  • Measuring results: The Business Case is then used to verify that the impact of the solutions not only brings operational benefits but also translates into the organization's accounts.

The Business Case is used more the more complex the problem is, and therefore costly to solve. It will then be necessary to justify the investment in human and financial resources to solve the problem. It will be used less for simple problems, or in a very simplified way, for example, when the "Kaizen" method is used.


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Saturday, 13 July 2024