How to Use ISO 21502 and the Global Best Practice Project Methodologies

Organisations execute much of their strategy through projects. Entering markets, introducing products, improving services and transforming operations all require coordinated change.

Yet approving a project does not guarantee that the intended business improvement will follow. A team can deliver what was requested, within its agreed budget and timescale, while the organisation gains little value.

For business leaders, this raises a practical question: how do we create a consistent approach to project delivery that keeps the strategic purpose visible?

ISO 21502 provides a useful starting point.

ISO 21502:2020 is an international standard offering guidance on project management. It applies across organisations and project sizes, accommodating predictive, iterative, adaptive and hybrid delivery approaches. It describes good management practices at a high level, allowing organisations to adapt their application to the work involved. ISO’s overview.

My recommendation is to use it as a reference for examining how your organisation turns investment decisions into business results.

That examination should begin with the why.

We understand this instinctively in our personal lives. We replace a car because repair costs are rising. We accept a job closer to home because we want more time with our family.

The purchase or job change is the action. Reliability, lower costs or additional family time provides the reason.

The same discipline belongs in project investment decisions. “Implement a new customer management system” describes a proposed solution. It does not explain which business problem deserves investment, whether the solution is appropriate or what improvement would justify its cost.

A stronger justification might be: “Reduce customer losses by improving the speed and consistency of account management.”

That statement creates a basis for evaluating options, defining success and challenging unnecessary scope.

It also helps distinguish three connected concepts:

Any target needs an agreed starting point, a measurement method and an accountable business owner. The assumptions also need testing: will improved follow-up materially influence retention, and what other factors could affect the result?

This is where strategy execution becomes practical. The organisation connects an objective to changed behaviour and measurable performance.

ISO 21502 also sits within a wider landscape of professional guidance. Business leaders frequently encounter PMI’s PMBOK Guide, PRINCE2 and the Association for Project Management’s Body of Knowledge. They serve different, complementary purposes.

ISO 21502 offers an internationally recognised reference for project management practices. I would use it to establish a common baseline across departments or assess whether an existing approach has significant gaps. Its flexibility is useful where projects vary considerably in size and delivery approach.

PMI’s PMBOK Guide, now in its eighth edition (2025), combines principles, performance domains and practical guidance, with an emphasis on value, adaptability and accountability. Published in November 2025, it includes expanded coverage of artificial intelligence, procurement and project management offices. It provides a resource for developing and tailoring management practices. PMI’s current edition.

PRINCE2 Project Management, Version 7 (2023), provides a structured method with defined principles, practices, processes and responsibilities. It can help organisations establish consistent arrangements for directing and managing projects. The current version explicitly addresses people, sustainability, and digital and data management, alongside tailoring to project circumstances. PeopleCert’s overview.

APM’s Body of Knowledge (2025), now in its eighth edition, provides a broad foundation for professional practice. It is methodology-neutral guidance rather than a single delivery method. The edition strengthens coverage of strategic context, leadership, sustainability, systems thinking, and data and artificial intelligence. It is useful for developing the capability and judgement of people responsible for change. APM’s current guidance.

My practical interpretation is that these resources can work together. An organisation might use ISO 21502 as its reference baseline, PRINCE2 to structure project governance, and PMI and APM guidance to strengthen delivery practices and professional capability.

The choice should follow the organisation’s needs. Introducing additional terminology and templates has little value unless it improves decisions and delivery.

For an organisation reviewing its approach, I would start with five actions:

1. Connect each project to strategy. Identify the objective it supports and why it deserves resources now.
2. Assign business ownership. Give a sponsor responsibility for the justification and identify who will own each benefit.
3. Apply proportionate controls. Match planning, reporting and decision requirements to complexity, uncertainty and potential consequences.
4. Review the business case. Revisit costs, risks and expected benefits as evidence develops. Be prepared to change direction or stop.
5. Plan adoption and measurement. Prepare operational teams to use the deliverables and assess benefits after handover.

These actions make the approach relevant to everyday management. They also expose problems that a delivery schedule alone may miss: unavailable business resources, weak assumptions or benefits nobody has accepted responsibility for achieving.

ISO 21502 cannot guarantee success. Its value comes from helping an organisation establish and apply sound management practices consistently. For leaders, the test is whether projects are producing the changes their strategy requires—and whether those changes deliver worthwhile results.

If you would like to review how your organisation connects strategy, project delivery and benefits, get in touch for a free initial consultation.