In today’s world of software development, the pressure to make fast decisions can significantly weigh on you and your team. And conventional wisdom often dictates that early decisions lead to clear plans and predictable outcomes. However, in their groundbreaking book, Lean Software Development: An Agile Toolkit, Mary and Tom Poppendieck challenge this notion with their third principle: Decide as Late as Possible. This concept, which may seem counterintuitive, is not an endorsement of procrastination but a powerful strategic approach that you and your team can use to manage uncertainty and build better, more resilient software.
Following the principles detailed in my articles on Eliminate Waste and Amplify Learning, the principle of delaying decisions intelligently can enable your team to leverage the knowledge gained through feedback and iteration, helping it make more informed choices. 2025 is a year already characterized by the rapid evolution of AI systems, dynamic cloud ecosystems, and intense market pressures. The principle of “decide as late as possible” has become more crucial than ever. It can provide your development team with a framework for creating change-tolerant systems and avoiding the costly consequences of premature commitments.
The Pitfalls of Premature Decisions
The more traditional software development models, such as the waterfall approach, emphasize making detailed decisions early in the process. Requirements are gathered and frozen, architecture is finalized, and a comprehensive plan is created before significant coding begins. The rationale is that the cost of fixing a problem escalates dramatically the later it is found in the development cycle. However, this approach has several fundamental flaws, especially in today’s uncertain environment:
Decisions Based on Speculation: Unfortunately, early and quick decisions are often based on incomplete information and speculation rather than hard facts. We need to be aware of how our customers’ needs evolve, market conditions shift, and technology advances, as these factors frequently render most early commitments obsolete.
Reduced Flexibility: Once a decision is made and built upon, it becomes increasingly difficult and expensive to change. This “depth-first” approach locks the project into a specific path too early, preventing a development team from adapting to new information or opportunities.
Increased Risk of Major Errors: By narrowing the field of view prematurely, teams are more likely to overlook critical system aspects or make fundamental architectural mistakes that are costly to correct later.
Concurrent Development: The Lean Alternative
The Poppendiecks advocate for an alternative inspired by lean product development: Concurrent development. Instead of a sequential process, your team’s different activities overlap. Programming can already begin when only the high-level requirements are known, and the design emerges and evolves through short, iterative cycles. This approach allows your team to learn by trying various options before committing to a final direction.
This methodology is powerfully illustrated by the automotive industry’s approach to creating the metal dies used for stamping car body panels. In the 1980s, U.S. automakers used a sequential process, freezing the design before sending it to the die makers. In contrast, the Japanese tool and die suppliers began their work concurrently with every car’s design. They collaborated closely with their clients’ automotive engineers and anticipated changes to their designs. This concurrent approach allowed them to delay final decisions, thus resulting in better designs, lower costs, and a faster time-to-market.
Similarly, concurrent software development requires close and active collaboration between your developers, customers, and analysts, ensuring that the system evolves to meet the actual business problem.
The Core Principle: Delaying Decisions for Maximum Advantage
Deciding as late as possible is about creating a capacity for change. I cannot overstate the value of this statement. It is an options-based approach that acknowledges the inherent uncertainty in software development and uses it as an advantage.
Options Thinking
Financial markets use “options” to manage uncertainty; the right, but not the obligation, to take an action in the future. These options allow investors to delay decisions until more information is available, limiting downside risk while maximizing upside potential.
We can view Agile software development as a process of creating such options. By keeping design choices open, your team can adapt to changing customer needs and relevant technological advancements. As Harold Thimbleby noted, experts instinctively delay firm commitments. At the same time, they investigate a new situation, knowing it leads to better insights. Amateurs, on the other hand, tend to make early, and often wrong, decisions. Premature commitment is a design failure that restricts learning and increases the cost of change.
The Last Responsible Moment
Our goal is to delay decisions until the Last Responsible Moment, the point at which failing to make a decision would eliminate a vital alternative or prove more costly than making the decision itself. This process is not procrastination; it is an active strategy that does require significant effort, as well as a specific set of tactics.
The Poppendiecks outline several such tactics for achieving this:
Information Hiding and Interfaces: This involves us structuring our software components in a way that conceals their internal implementation details while exposing only well-defined interfaces. By separating the interface from the implementation, your developers can modify the internal design of a module without impacting other parts of the system that rely on it. This modularity reduces the ripple effects of changes, making maintenance and evolution more manageable and less costly, both for you and your client. For example, a module responsible for data storage might expose methods like saveRecord() and loadRecord(). Nonetheless, we will be able to change the underlying database technology (SQL, NoSQL, flat file) without altering the code that calls these methods.
Think Abstractions, but use Disposable Code: When Lean Software Development: An Agile Toolkit was written, the authors recommended using abstractions. This was supposed to allow developers to work with higher-level concepts and defer commitments to specific concrete representations. However, using abstract, generic code will lead to more complicated code. Luckily, we can now use disposable code, a trend that has become increasingly common in our age of AI. Thanks to the development of LLMS, coding has become much less time-intensive, affording us the luxury of being able to create multiple sets of code, each of which we can consider disposable. Doing so allows various design decisions to be tested. Using disposable code also keeps your team’s options open to adapt to changing requirements. For instance, designing a system to interact with a payment gateway via disposable code allows us to switch to new payment options easily by simply replacing the code.
Avoid Repetition: The “Don’t Repeat Yourself” principle dictates that we should express every piece of knowledge, capability, or logic in only one place within a system. Duplication leads to inconsistencies, as changes made in one place might not be replicated in another. This can result in bugs and increased complexity. By ensuring that a single source of truth exists for each capability, our changes become easier to implement and verify, and our overall system remains more coherent and robust. This applies not just to code but also to documentation, configuration, and even processes.
Separate Concerns: This principle focuses on assigning a single, well-defined responsibility to each module or component. This means that a module should have only one reason to change. If we were to mix concerns, a change related to one concern can inadvertently affect another, leading to brittle designs and difficulties in debugging. By clearly delineating responsibilities, your developers can ensure that modifications are localized and easier to manage. For example, a user interface component should primarily focus on display logic, while business logic should reside in a separate service layer, and data access in another.
Encapsulate Variation: Here, we identify parts of the system that are likely to change and isolate them. By encapsulating these volatile elements, our modifications do not propagate throughout the entire codebase, thereby limiting the impact of any changes. We can thus create boundaries around areas of anticipated instability, which makes our system more resilient to evolving requirements. For instance, consider a system that must support different tax calculation rules for various regions. We can encapsulate the tax calculation logic in a dedicated module or strategy pattern. In that case, we can allow for easy addition or modification of the tax algorithms without affecting the core application. This proactive approach to managing change is crucial if your team is designing systems for longevity and adaptability.
Flattening the Cost-of-Change Curve
A common justification for early decision-making is the belief that the cost of change escalates exponentially over time. While this holds true for a few fundamental architectural constraints, the Poppendiecks argue that for most changes, we can flatten this curve dramatically!
Taking concurrent development and change-tolerant design into account is crucial for achieving agility and efficiency in complex projects, especially in the context of the “Decide as Late as Possible” methodology. These approaches achieve their benefits through several key mechanisms:
Reducing the number of high-stakes, irreversible decisions: By adopting a concurrent development model, we can explore multiple options and gather more information before committing to critical paths. Your team can thus minimize the frequency of making decisions that are difficult or impossible to undo, therefore reducing the risk associated with early, potentially misinformed choices. A change-tolerant design further supports this by anticipating and accommodating future modifications, lessening the impact of decisions that might otherwise be considered irreversible.
Allowing a breadth-first approach to those high-stakes decisions makes them more likely to be correct: Instead of locking into a single path prematurely, concurrent development enables the exploration of a broader range of alternatives. The breadth-first strategy for high-stakes decisions allows us to evaluate various solutions in parallel. This allows us to identify potential issues and compare different approaches before converging on the most optimal one. Such a comprehensive exploration significantly increases the likelihood of you and your team making correct and well-informed decisions, as it leverages a broader understanding of the problem space and potential solutions. I will be comparing breadth-first and depth-first approaches in the next section.
Deferring the bulk of decisions significantly reduces the need for subsequent changes: The “Decide as Late as Possible” principle, facilitated by concurrent development and change-tolerant design, advocates for postponing decisions until the last responsible moment. This delay allows you and your team to accumulate more accurate and complete information, reducing the likelihood of making choices that later prove to be suboptimal, requiring extensive rework. By making decisions when the context is clearer and the requirements are more stable, we minimize the ripple effects of early decisions and the subsequent need for costly and time-consuming modifications.
Dramatically decreasing the cost escalation factor for most changes by building a system designed to evolve: A core tenet of change-tolerant design is building systems with an inherent capacity for evolution. This means designing with modularity, loose coupling, and clear interfaces, which allows for individual components to be modified or replaced without disrupting the entire system. When your team designs a system to evolve, the cost of implementing changes, even significant ones, remains relatively low. Evolving systems stand in stark contrast to rigid systems, where even minor alterations can trigger a cascade of expensive and complex adjustments, leading to a dramatic escalation in the cost of change over time. By embracing evolution from the outset, projects can adapt to changing requirements and new information much more efficiently and economically.
Making Decisions Effectively
Delaying decisions is only half the battle; you and your team must eventually make them. The Poppendiecks highlight that the quality of decision-making is paramount.
Breadth-First vs. Depth-First Problem Solving
Depth-First: This approach involves making early commitments to narrow down the problem’s complexity. It carries the risk of choosing the wrong path and losing the work done when a change of course is needed. This approach, characterized by making early commitments, aims to simplify complex problems by narrowing down the scope of possibilities.
While it might offer your team the benefits of focused effort and potentially quicker initial progress, it inherently carries the significant risk of them committing to an incorrect path. Should a change of course become necessary due to new information or unforeseen circumstances, the work that your team has already invested in the initial direction could be entirely lost, resulting in wasted resources, time, and effort on their part. This necessitates a careful consideration of the trade-off between early clarity and the potential for costly rework if the chosen direction proves suboptimal.
Breadth-First: This strategic approach advocates for you and your team to intentionally delay your firm commitments and decisions, instead prioritizing you to undertake a comprehensive survey of all available options and the overarching landscape. It emphasizes a broad exploration before narrowing focus and delving into specific details. This methodology is particularly effective and should be your approach of choice when your team faces dynamic and evolving domains or environments.
Deferring early specialization grants your developers significant flexibility, enabling them to continuously adapt to new information, emerging challenges, or shifting priorities. It stands in contrast to the depth-first approach, which might cause your team to prematurely commit its resources and efforts to a single path. Such a decision could potentially lead to inefficiencies or missed opportunities when the circumstances change.
Expertise is crucial for both approaches, but the breadth-first approach is inherently more resilient to change.
The Power of Simple Rules
In complex, fast-moving environments, your team’s decisions cannot always be escalated up a chain of command. Effective organizations empower frontline teams to make decisions based on a small set of simple, guiding rules. These rules communicate the organization’s intent, allowing for rapid, coordinated, and autonomous action.
The seven principles of Lean Software Development themselves serve as such rules. They provide a framework for teams to make sound, intuitive decisions without constant supervision by higher management.
Relevance in 2025: Why Deciding Late Is More Critical Than Ever
The software landscape of 2025 continues to make the principle of “Decide as Late as Possible” indispensable.
AI and Machine Learning: The development of AI systems is highly experimental. The best model, architecture, or data pipeline is rarely known upfront. A breadth-first, set-based approach, exploring multiple options simultaneously before committing, is essential for success. Delaying the final choice of an AI platform or framework until its capabilities are better understood can prevent costly lock-in.
Cloud-Native Architectures: The cloud offers a vast array of services (e.g., serverless, containers, managed databases). Making an early, irreversible decision on a specific service can be risky. Testing before making a decision remains as vital as ever. A flexible architecture that uses interfaces and abstractions allows a team to defer commitment, making it possible to swap out a service later if a better or more cost-effective option emerges.
Accelerated Market Cycles: Market demands and competitor actions change faster than ever. Locking into a feature set or a rigid architecture a year before release is a recipe for irrelevance. Delaying decisions allows products to adapt to the latest market trends right up to the delivery date.
Platform Engineering: The rise of internal developer platforms aims to provide developers with stable, reliable tools and infrastructure. However, the platform itself must be built with flexibility in mind. Deciding late on which specific tools or services to integrate into the platform allows the platform team to learn from developer feedback and choose solutions that genuinely improve productivity.
Conclusion: The Strategic Value of Patience
The principle of “Decide as Late as Possible” is not about indecision. It is a sophisticated strategy for managing risk and maximizing value. This especially holds in today’s world of uncertainty. It challenges the ingrained belief that comprehensive upfront planning is the safest path for a software developer. Instead, the Poppendiecks’ work shows us that we need to embrace concurrent development, thinking in options, and empowering teams with simple rules. With this mindset, we can build systems that are not only correct for today but are resilient enough to adapt to the challenges of tomorrow.
In 2025, the ability to navigate change is the ultimate competitive advantage. By mastering the art of delaying a commitment to the last responsible moment, you will be able to flatten the cost-of-change curve, foster innovation with your team, and deliver products that genuinely meet the evolving needs of your users. The wisdom of this lean principle is timeless, providing a powerful guide for building successful software in our complex and dynamic world. In my next article, I will be aiming to expand this by looking at the fourth chapter of Lean Software Development: An Agile Toolkit; Empower the Team.
