Lean vs. Agile: What Are They, and Which Is Best for Your Project?

What Is Lean Software Development?

Lean software development was inspired by the Lean manufacturing movement of the 1980s. At the heart of this movement is reducing time within a production system as well as response times from suppliers and to customers. This methodology places a premium on optimizing efficiency and minimizing waste at every level of a process, including individuals, departments, company-wide operations, the company itself, and between organizations, customers, and suppliers.

Lean software development was originally coined by Mary and Tom Poppendieck in their book, Lean Software Development, which was published in 2003. In this book, the authors identified seven Lean principles and adapted them to software development. They also introduced 22 “thinking tools” that can help companies customize agile practices for any development or business environment. With these principles, your company can experience better, cheaper, and faster software development.

Ultimately, the foundation of Lean software development services focus on value, flow, and people in order to achieve less waste and a more effective development cycle. Any Lean software development company will find they’ll not only save money in the process but also profit from the added efficiencies.

Lean Principles

There are seven core principles to Lean software development, each of which must be implemented in order to achieve a successful lean process. These principles are:

Eliminate waste. Once an iteration is complete, stakeholders discuss issues found in the process and identify waste, which is anything that doesn’t add value to the product. The goal here is to develop an actionable plan to eliminate waste like unnecessary code, tasks that weren’t completed, red tape, and Q&A issues.
Build in quality. For this you can use techniques such as pair programming (two developers at one workstation) and test-driven development (repeatedly testing software against all test cases).
Amplify learning. Share knowledge between developers via code review and meetings. This also implies that software developers are encouraged to question assumptions.
Delay commitment as long as possible. Ensure there’s an experiment/test/learn phase of the development cycle that goes on as long as needed before committing the project to decisions that cannot be changed without considerably bottlenecking the project.
Deliver fast. Fail fast and learn. Launch a product quickly, and use feedback to improve the next iteration.
Respect people. Lean software development encourages respect for all stakeholders in the process. It’s also important to encourage healthy conflict, proactive communication, and a constant stream of feedback.
Optimize the whole. The software development cycle is carefully examined from start to finish. The goal here is not only to produce optimal code quickly but also to make sure the entire process is running at peak efficiency.

Advantages / Pros of Lean

Of course, every methodology has advantages, and Lean software development is no exception. Here are some of the pros of adopting Lean:

The streamlined process allows for better software and functionality to be delivered more quickly.
You will eliminate unnecessary pieces of the process, which in turn can reduce overall costs.
Your teams are empowered to make their own decisions, which greatly improves the decisions made and also improves company morale.
Heightened collaboration between teammates makes for a more efficient and reliable process. This also leads to a greatly improved product, as your developers are constantly discussing the process and the product.
A flexible workflow is also a priority, which means your developers can easily bend and shift the process as needed.

Disadvantages / Cons of Lean

Lean software development does come with a view disadvantages as well:

It is not as scalable, given how tightly integrated the teams must be.
It requires very strong documentation to keep things moving and iterating.
It can lead to a very complex process that requires the full attention and dedication from every team member.
It can lead to breaking the process into too many small parts, each of which can be suboptimal for the whole.

What Is Agile Software Development?

Agile software development can be summarized as an iterative approach to software development that focuses on delivering value to customers quickly, using a highly efficient process. Agile focuses on incremental delivery, team collaboration, and continual planning and learning.

It is the iterative principle that sets Agile apart from other methodologies. With Agile, it’s more important to release often and improve the product with every release. This is a shift away from the slower, more costly process of developing, beta testing, beta releasing, Q&A testing, bug fixing, and final release cycle that has been prevalent for so many years. Agile is all about short development cycles, failing fast, getting feedback, and iterating the product.

Agile software development was based on the Agile Manifesto, which places a premium on the following:

Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan

The Agile Manifesto was born of a meeting between seventeen people at The Lodge at Snowbird ski resort in the Wasatch mountains of Utah to find a common ground in the search for a methodology to replace the document-driven software development process. From that meeting the seeds of Agile software development services would be sown, which would then lead to the birth of Agile software development companies across the globe.

Agile Principles

There are 12 principles behind Agile software development:

Satisfy clients through continuous and early delivery of reliable and functioning software.
Embrace change throughout the software development cycle.
Iterate as often as possible, even every two weeks or month. The shorter the iterative timescale, the better.
All stakeholders should work together throughout the process.
Create teams of motivated people and give them an environment that encourages success.
Rely on face-to-face communication, instead of only messaging, emails, and forums.
Functioning software is the measure of progress.
Sustainability is key. All stakeholders in the process should be able to sustain the required pace for the iterations.
Constant attention to excellence across the process.
Simplicity is essential.
Teams must be self-organized.
Teams self-examine at regular intervals to find ways to improve their processes.

Advantages / Pros of Agile

The Agile software development methodology has a number of key advantages, such as:

Superior product delivery, which is a product of the iterative approach and frequent testing.
Customer satisfaction, which comes from the customer feeling as though they are a part of the process.
Transparency of the process leads to managers having more control, without controlling developers.
Thanks to observability and monitoring, Agile produces more predictable projects.
Less risk of failure, due to the iterative nature and short development sprints.
Increased flexibility of the process means it can shift when necessary.

Disadvantages / Cons of Agile

Although Agile might sound like the ideal process, it’s not without its disadvantages, such as:

Resource planning is challenging due to the inability to predict the end result of the product.
Documentation isn’t given the usual priority.
The iterative nature means the process as a whole can become fragmented, with teams working at different speeds on different pieces of the project.
Because of the iterative nature, there’s often no definite end of the process.

Key Differences Between Lean & Agile

	Lean	Agile
Popularity	Popular in manufacturing industries and becoming more prevalent in software development.	Widely adopted in software development, and gaining traction in other project management fields.
Applications	Ideal for projects that aim to minimize waste and maximize efficiency.	Ideal for projects with unpredictable requirements, where flexibility and responsiveness are key.
Key Advantages	Minimizes waste Maximizes customer value Focuses on continuous improvement	Embraces change Delivers working software rapidly Promotes close customer collaboration
Key Disadvantages	Requires a cultural shift and buy-in at all levels May need significant changes in current processes	Can be chaotic if not well managed Requires customer and team involvement throughout the project
Cost-Effectiveness	Can be cost-effective by reducing waste and improving efficiency.	Can be cost-effective by delivering valuable features early and frequently.
Infrastructure	Requires an organizational structure that supports continuous improvement and waste reduction.	Requires an organizational structure that supports flexibility, collaboration, and customer interaction.
Training	Specific Lean training is necessary to understand its principles and tools.	Agile training is necessary, including understanding of roles (like product owner, scrum master) and processes (like sprints, retrospectives).
Communication	Regular communication for process improvement is key.	Frequent and close communication among team members and with the customer is crucial.
Flexibility	Highly flexible with a focus on improving processes and eliminating waste.	Highly flexible with the ability to adapt to changes and deliver incremental results.
Security	Mid; Lean doesn’t inherently address security, but it can be integrated into the process improvement efforts. Explain: While Lean focuses on efficiency and waste reduction, security measures need to be consciously integrated into the processes.	High; Agile’s iterative approach allows for regular security checks and improvements. Explain: Regular sprints and reviews provide opportunities to check and improve security measures.
Tools and Processes	Uses tools like Kanban boards, value stream mapping; follows processes like Just-in-time, Jidoka.	Uses tools like Agile boards, burndown charts; follows processes like sprints, daily standups.
Agreements	Long-term commitment to continuous improvement.	Short-term commitments in the form of iterations or sprints.

One of the biggest differences between Lean and Agile is that the Lean methodology increases speed by managing the flow of the process. On the other hand, Agile increases speed by iterating in small increments (often done during sprints).

Another key difference is that Agile places a priority on open and constant feedback between the developers and the users, whereas Lean places a priority on eliminating aspects of the project that the customer or user would consider waste.

The Agile methodology is also more structured than Lean, with defined roles, structured meetings, estimations, and systemic and frequent reviews.

Lean Kanban vs. Agile Scrum

One key difference between these two methodologies is the software used to manage the projects. Where Lean software development focuses on traditional tools, such as Kanban, Agile turns a good amount of its attention to Scrum. Although both methods do use Kanban boards, Agile tends to depend on the Scrum sprint, where Lean can function just fine with a standard Kanban board.

What Does the Future Look Like?

The future of Lean and Agile methodologies is hard to predict, but it would come as no surprise if these two ideas came together to form a newer, more efficient and effective method. It would also be a safe bet to say that automation and AI will become instrumental in improving and transforming both of these methods.

And with the continued growth of containerization, the Agile methodology will become even more widely used, especially with the spread of CI/CD. As more and more businesses adopt containerization, serverless, and CI/CD, the Agile software development methodology will gain considerable market share over Lean.

Lean vs. Agile: Who Wins?

The winner between these two will be defined by the trends in software delivery methods. If containerization and CI/CD continue to grow exponentially, Agile will win out. If businesses start to pull away from containerization (for reasons such as security and complexity), Lean will become the more popular methodology.

Another issue is small and midsize businesses (SMBs) vs. enterprise businesses. Most enterprise-scale businesses are dependent upon containerization and the cloud, whereas SMBs tend to go for more traditional approaches to software. As more SMBs scale to enterprise growth levels, they’ll start adopting more scalable, flexible technologies. That translates to more Agile methodologies being applied.

But how do you know which methodology to choose?

When to Use Lean

If your company is looking to eliminate waste in the software development process, the Lean methodology might be ideal. Starbucks is a perfect example of this. To eliminate a $2 million revenue gap, the company adopted the Lean methodology to resolve an issue with a low-selling breakfast item.

If your company depends on repetitive, predictable processes, the Lean methodology is the way to go. No matter if your company makes cars, spreadsheets, or mobile apps, if you’re looking to improve the overall process to deliver a higher quality product, Lean is what you want.

When to Use Agile

Simply put, Agile is the best methodology when a product or product features are not well defined. Because Agile relies heavily on an iterative approach, the product evolves as each iteration is complete. Agile is also a great option when continuous delivery/continuous integration is required, as the Lean methodology isn’t nearly flexible enough to handle these types of processes.