Few questions generate more debate in project management circles than this: should we use agile or waterfall?
And while the debate is often framed as a simple binary choice, the reality facing most project managers today is considerably more nuanced. Most organizations operate across a spectrum of delivery approaches — running some projects in a highly structured, predictive way; others in fast, iterative agile cycles; and many in a hybrid of both.
Understanding the strengths and limitations of each approach, and knowing how to choose the right one for a given context, is one of the most valuable skills a project manager can possess.
Understanding Waterfall (Predictive) Project Management
The waterfall — or predictive — approach to project management involves planning the full scope of work upfront and executing it in a series of sequential phases: initiation, planning, execution, monitoring and control, and closure.
This approach assumes that requirements can be defined clearly at the beginning of a project and that change, once work has begun, is undesirable and costly. It prioritizes comprehensive planning, detailed documentation, and rigorous change control.
When waterfall works well:
- Requirements are well-understood and unlikely to change significantly
- Regulatory or compliance requirements demand comprehensive documentation
- The project involves physical deliverables (construction, manufacturing) where sequential phases are inherent
- Contractual or procurement structures require fixed scope and price
- Stakeholders prefer detailed upfront plans and formal approvals
Typical industries: Construction, engineering, infrastructure, defense, government, regulated industries
Limitations:
- Less responsive to changing requirements
- Value is only delivered at the end of the project
- Problems are often discovered late, when they are more expensive to fix
- Can create excessive bureaucracy and administrative overhead
Understanding Agile Project Management
Agile approaches are based on iterative, incremental delivery. Rather than planning everything upfront and delivering at the end, agile teams break work into short cycles (sprints or iterations), deliver working outputs frequently, and continuously adapt their plans based on feedback and changing circumstances.
The Agile Manifesto’s four core values — prioritising people over processes, working deliverables over documentation, collaboration over contract negotiation, and response to change over following a plan — underpin all agile frameworks.
When agile works well:
- Requirements are evolving or not yet fully understood
- Speed to market and early delivery of value are priorities
- The project involves complex problem-solving where upfront planning is impractical
- Stakeholders are available and willing to engage regularly in shaping the product
- The team is empowered to make decisions and self-organise
- Innovation and experimentation are valued
Common agile frameworks: Scrum, Kanban, SAFe, LeSS, DSDM, XP
Limitations:
- Requires high levels of stakeholder engagement that not all organisations can sustain
- Documentation may be less comprehensive, which can be problematic in regulated environments
- Can be challenging to implement on fixed-scope, fixed-price contracts
- Scaling agile across large, complex programmes is non-trivial
Understanding Hybrid Project Management
Hybrid project management blends elements of both predictive and agile approaches to create a delivery model that suits the specific needs of a project, team, or organization.
Hybrid approaches recognize that few real-world projects are perfectly suited to a pure agile or pure waterfall model. Most involve some elements of both — perhaps a structured project initiation and governance framework combined with iterative, agile delivery within that structure.
Common hybrid patterns:
- Waterfall at the programme or portfolio level, agile at the project or team level
- Agile delivery of software components within a waterfall infrastructure project
- Fixed scope and price contract (waterfall) with agile internal execution
- Structured initiation and closure phases with agile middle phases
When hybrid works well:
- Large, complex programmes with multiple delivery tracks operating at different speeds
- Organisations transitioning from waterfall to agile who need a managed evolution
- Projects where some elements are well-defined (waterfall) and others are exploratory (agile)
- Environments where governance and compliance requirements coexist with the need for speed and adaptability
How to Choose the Right Approach
The right methodology for any project depends on a careful analysis of several factors:
Requirement Clarity
How well-defined are the requirements? If they are clear and stable, waterfall may be appropriate. If they are evolving or uncertain, agile offers more flexibility.
Rate of Change
How likely are requirements to change during the project? High volatility favours agile; low volatility makes waterfall more practical.
Stakeholder Availability
Agile requires active, ongoing stakeholder engagement. If key stakeholders are not available to participate regularly in reviews and backlog refinement, a more structured approach may be needed.
Regulatory Environment
Regulated industries often require comprehensive documentation and formal approval gates that are more naturally aligned with waterfall or hybrid approaches.
Team Experience and Mindset
Agile works best with empowered, self-organizing teams that are comfortable with ambiguity. Teams accustomed to detailed instructions and hierarchical decision-making may struggle with the autonomy agile requires.
Delivery Urgency
If early, partial delivery of value is important — getting something to users quickly and learning from it — agile’s incremental approach is advantageous. If the value can only be realised when the full product is complete, this advantage diminishes.
Why Methodological Fluency Matters
The most valuable project managers today are not advocates for a single methodology. They are methodologically fluent — equipped with the knowledge and experience to assess a given context and select, adapt, or blend the approach that is most likely to lead to successful delivery.
This fluency is precisely what the PMP (which covers predictive, agile, and hybrid approaches) and the PMI-ACP (which focuses specifically on agile) are designed to develop and validate.
How RMC Learning Solutions Develops Methodological Fluency
Our training programmes for the PMP and PMI-ACP are designed to develop not just exam-ready knowledge, but genuine methodological fluency — the ability to think clearly about delivery approaches and make sound choices in complex, real-world environments.
Explore our training programs and develop the versatility that modern project management demands.
Published by RMC Learning Solutions — Preparing Project Managers for Success Since 1991.





