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Lean vs. Six Sigma vs. agile – what is the difference between these methodologies?
In this post, we’ll explore the answer to that question, and we’ll also learn the pros and cons of each, as well as other alternatives to these process improvement methodologies.
Lean vs. Six Sigma
Let’s begin by looking at lean.
What is lean?
Lean is business methodology aimed at achieving aims such as:
- Improving quality
- Reducing waste
- Increasing customer value
The methodology began in manufacturing, but it is since spread to many other disciplines from product development and product management to supply chain management.
It is founded on principles such as continual improvement, which is the idea that performance improvement should be an embedded feature of the business.
Lean is a relatively easy to understand system and it usually generates positive results, which is perhaps why it has become so popular in recent years.
Using lean, for instance, businesses will often realize benefits such as:
- Improved business efficiency
- Increased customer satisfaction
- Lower business costs
- Reduced time-to-market
Reducing waste, such as useless labor or transportation, is one of the key means by which lean can achieve these goals – and, as mentioned, this is one of the primary focuses of the methodology.
Yet there are other ways to achieve the same benefits without focusing so heavily on waste reduction.
Six Sigma offers a different approach.
What is Six Sigma?
Six Sigma is another process improvement methodology that aims to systematically and continually optimize processes. Like lean, many of its benefits include:
- Increased business efficiency
- Reduced costs
- Increased customer satisfaction
- Better Business outcomes
However, whereas lean focuses on waste reduction, Six Sigma focuses on reducing variation and defects.
To this end, Six Sigma relies heavily on data-driven processes, statistics, and scientific approaches to solving business problems. Also, since the focus of Six Sigma does differ from lean, the outcomes will also differ to a certain extent.
For that reason, some use a hybrid approach that combines elements from both lean and Six Sigma.
What is Lean Six Sigma?
Lean Six Sigma, unsurprisingly, attempts to combine the best of both lean and Six Sigma into a single methodology.
For instance, goals for Lean Six Sigma can include:
- Reducing waste
- Reducing product defects
- Minimizing variation within systems
- Maximizing customer satisfaction
Lean Six Sigma has in fact become so popular that there are a number of certifications in this method. However, even these certifications have their own emphases and structure.
Which Is Best – Lean, Six Sigma, or Lean Six Sigma?
Each approach has its pros, cons and use cases – we cannot say that one is “better” than any other. Instead, every business should define its own goals, values, and culture, then choose a system that aligns with those.
For instance, a company that is very data-driven and methodical may prefer Six Sigma.
A company, on the other hand, that wants a minimal system built around continual improvement may prefer lean.
A company that wants the best of both worlds may choose Lean Six Sigma.
Finally, a company that wants yet another approach may choose something else entirely.
Agile vs. Lean vs. Six Sigma
Lean and Six Sigma generate positive outcomes for the most part. Yet they are not without criticism.
One common criticism of process improvement methodologies such as these is that they are too narrow. Six Sigma, For instance, focuses exclusively on reducing variation. It cannot therefore be useful for innovation or adaptation.
For that, a different approach is needed.
Agile is not a methodology.
Instead, it is a set of values.
Those values revolve around:
- Responsiveness and adaptability
- Continual collaboration with stakeholders
- Functionality over static processes and documentation
While lean and Six Sigma remain focused on improving processes, agile focuses on adaptation, change, change management, and staying nimble in the face of disruption.
For example, during the COVID-19 pandemic, agile businesses were willing to restructure, build new processes in order to stay relevant and effective. This contrasts with the two approaches covered above, which focus on a continual gradual optimization rather than rapid change and adaptation.
Despite the differences between agile and the other systems covered above, these systems are not mutually exclusive.
In fact, one could adopt all of these approaches – lean, six sigma, and agile.
This would result in what is also called a hybrid approach, often used in software development. In this approach, businesses will selectively adopt and combine principles to form an approach that is part agile and part linear. The same tactic can be used to combine lean with agile or any of the other methods mentioned above.
Final Thoughts
Process improvement methodologies have become normal in today’s business environment, and for good reason. They can be used to increase a number of business metrics, from costs to customer satisfaction.
Without being said, every business methodology has its own area of focus. It cannot therefore be relied upon to improve areas outside that scope.
To overcome these deficiencies, it is often best to survey a number of business methodologies and process improvement methodologies, then adopt a process that combines elements from each.
