The Continuous Improvement Blog

Problem solving tools for business improvement - PDCA, SIX SIGMA & 8D

Written by Colin McArdle on 20 Dec 2017

six_sigma_problem_solving.pngIt’s no secret that problem-solving and improvement activities are crucial for sustaining effective business operations.

It is not uncommon for Managers to expect staff and new hires to be capable of fixing workplace problems.  However, problem-solving outcomes are impacted because staff are not provided the time to think or trained in basic problem-solving methods such as PDCA, Six Sigma and 8D.

With a variety of problem-solving tools being used by Managers, how do you know which is the best approach? Even with a wealth of experience, the multitude of approaches can be confusing.

In this blog post, we outline three key problem-solving tools used for business improvement, uncover the differences and similarities of each, and discuss when to apply them.

First, it’s important to point out that problem-solving tools tend to focus on eliminating the root cause. Typically, they are structured and involve the following stages:

  • Define the problem or issue to be improved
  • Gather data and evidence
  • Identify factors that contribute to the problem or issue
  • Find the root cause
  • Develop a solution
  • Implement the solution
  • Observe the outcome to ensure effectiveness

Plan, Define, Check, Act (PDCA)

PDCA is a classic problem-solving approach of a Lean methodology. It aims to improve the quality and effectiveness of processes, and follows four stages:

  • Plan - Establish the objectives and processes necessary to deliver results in line with requirements;
  • Do - Implement the required objectives and processes planned;
  • Check - Monitor and evaluate the results against initial objectives and report the outcome;
  • Act - Apply any actions needed for improvement to the outcome. Review all steps above and modify processes as required and continue the next cycle of PDCA.

The ‘Plan’ phase is most important, and usually consumes at least half of the total time. This is where the issue is defined, data is gathered and a root cause identified. Once the ‘Act’ phase has been completed, the cycle should start again and live on as a continuous improvement tool.

PDCA can be used in many areas of a business, including supply chain, HR, and project management to address medium-sized problems.

Six Sigma - Define, Measure, Analyse, Improve, Control (DMAIC)

Six Sigma uses a structured methodology and is used to solve complex or chronic problems. It specifies a sequence of phases to drill-down to the root cause of a problem and eliminating, reducing, or controlling the cause from recurring:

  • Define - Define the problem, goals, customer requirements and the business case for change;
  • Measure - Measure the process accurately to determine current, baseline performance;
  • Analyse - Analyse and determine the root cause or causes of the problem;
  • Improve - Improve the process by eliminating or reducing the probability of root cause recurrence;
  • Control - Control and sustain the improved performance by monitoring the process.

At the end of each phase, a formal review is conducted by the project team and key stakeholders, to ensure key deliverables are completed and approved before the next phase begins.

DMAIC is typically used to tackle large problems where a great deal of data needs to be analysed. Due to the nature of the problem, it may be used alongside statistical analysis tools.

A typical DMAIC project may last over three months, depending on the complexity of the problem and the process to be improved.

Eight disciplines (8D)

8D was first introduced by the US Government as a problem-solving tool for the automotive industry. The aim is to use cross-functional teams to find the root cause of a problem, devise a short-term fix, and implement a long-term solution to prevent problems from recurring.

The eight disciplines are:

  • D1 - Assemble a cross-functional team of knowledgeable people;
  • D2 - Define fully the problem;
  • D3 - Implement interim containment actions as required;
  • D4 - Identify and verify root causes;
  • D5 - Choose and verify permanent corrective actions;
  • D6 - Implement and validate actions taken;
  • D7 - Prevent recurrence of the problem;
  • D8 - Recognise the efforts of the team.

Where the use of 8D is mandated, such as in the Automotive Industry, the emphasis is on fast reactions. As a result, the first three stages are typically accomplished and reported in just three days. It is also used to react to safety or regulatory issues, or when performance is occurring at unacceptable levels. 

So what’s the difference and which should I use?

Lean uses PDCA in a cyclical approach for continuous improvement, improving every day, where every problem is approached using PDCA.  

DMAIC hails from the Six Sigma world and is used to solve complex or chronic problems.  

8D is similar to PDCA but it is more prescriptive, mandating steps seeking evidence to move to the next discipline.

Lean and Six Sigma are applied across diverse industry sectors. 8D, though originally distinct to the automotive industry, is also now applied across a wide range of sectors.

Choosing the most appropriate tool often depends on the business rules, and the size and complexity of the problem.

DMAIC lends itself better to large complex problems where large amounts of data are involved, whereas PDCA is often more appropriate for solving small or medium-sized problems.  8D tends to be rule-based, driven by the quality management system and used for small and complex problems.

Being able to solve problems effectively and efficiently is crucial for maintaining optimum operational performance. Businesses using Lean and Six Sigma together as a dual approach benefit from being able to utilise a wide range of tools and pull on the right one at the right time to find a solution to a problem.

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Topics: Business Improvement

Colin McArdle

Written by Colin McArdle

Colin McArdle, the Founder and Managing Director of Kaizen Kulture is a Lean and Six Sigma Master Black Belt who has over 30 years industry experience. Kaizen Kulture's mission is to be true to the ethos of continuous improvement.