Agile, Lean, Scrum – What is What?

Agile, Lean and Scrum – do they mean the same thing? While some people may think these three notions are synonyms, though in reality, they look very similar but still have some significant differences.

In this article, we’ll take a closer look at these concepts and explain how they differ.

Origins

Agile

When we talk about Agile, the first thing we refer to is the Agile Manifesto created in February 2001 and its 12 principles that define the criteria for agile software development processes.

Any methodology that agrees with the Agile Manifesto and its 12 principles can be called ‘Agile’. The most well-known methodologies include Scrum and Extreme Programming. In other words, Agile is not a method – it’s a collective name for approaches that follow ‘Agile’ principles.

Scrum

As seen above, Scrum is an Agile software development framework. The word “scrum” was first used in 1986 as a term to describe “a new approach to commercial product development that would increase speed and flexibility”.

The basics of the modern Scrum are defined in the Scrum Guide. Scrum’s key principle is recognition that during product development, unpredicted challenges (e.g. customers can change their minds about what they need) can happen. That’s why Scrum focuses on maximising the team’s ability to adapt quickly and respond to new requirements.

Lean

Lean principles are derived from the Japanese manufacturing industry. The term “lean manufacturing” is used to describe a systematic method for the elimination of “waste” (defects, overproduction, etc.) within a manufacturing system to improve customer value – because “value” is the only thing customers are willing to pay for.

Similarities and differences

Agile and Lean both have clearly defined principles.

Agile principles:

• Highest priority is customer satisfaction
• Welcome changing requirements
• Frequent delivery of software
• Business people & developers cooperating daily
• Build projects around motivated people
• Face-to-face conversation is best
• Progress measured by working software
• Sustainable development pace
• Continuous attention to technical excellence
• Simplicity
• Self-organizing teams
• Regular reflection & adaptation

Lean focuses on:

• Eliminating waste
• Building quality
• Creating knowledge
• Commitment
• Fast delivery
• Respecting people
• Optimising the whole process

As we can see from these principles, there are many similarities, including the focus on quality and continuous improvement/optimisation/adaptation.

One of the main differences between Agile/Scrum and Lean is that Lean focuses a lot on eliminating waste – while Agile/Scrum focus on a constant adoption to changes in order to deliver value to the customer.

Moreover, Agile/Scrum, as well as Lean, focus on a speed delivery. But in the case of Agile/Scrum speed comes from simplicity that is defined as ‘the art of maximising the amount of work not done’. For lean, speed means building a solution, getting it to the market quickly and enhancing incrementally based on real customer feedback.