PMBOK and PRINCE2 dominate the project-management conversation, but there's a third reference that's vendor-neutral and internationally agreed: ISO 21502. It's guidance on the practices for project management — the successor to ISO 21500 — describing what good project delivery involves without tying you to one methodology or certification body.
Guidance, not a recipe
ISO 21502 doesn't prescribe a rigid process. It describes the practices that projects draw on, leaving you to apply them in the way that fits your context — predictive, agile, or hybrid. That neutrality is its strength: it's a common reference that sits above any single method.
The practices it covers
- Governance and the business case — why the project exists and who holds it accountable.
- Planning — scope, schedule, cost, and how they interrelate.
- Risk and issue management — anticipating and responding to uncertainty.
- Stakeholder engagement — the human side that sinks more projects than technical failure does.
- Benefits realisation — ensuring the project actually delivers the value that justified it.
A project that ships on time and budget but delivers no benefit is still a failure. ISO 21502 keeps benefits, not just delivery, in view.
Integrated management
A theme of the standard is that these practices aren't run in isolation — they integrate. Risk affects schedule, schedule affects cost, stakeholders affect scope. ISO 21502 frames the project manager's job as integrating these threads toward the intended outcome, not just administering each in a silo.
Where it fits among the alternatives
Think of ISO 21502 as the neutral map: PMBOK offers a detailed knowledge base, PRINCE2 a prescriptive method, and ISO 21502 an internationally agreed description of the practices both draw on. It's especially useful when you want a common vocabulary across teams that use different methods.
Deliver projects by the standard
My ISO 21502 course covers governance, the business case, planning, risk, stakeholders, and benefits realisation — vendor-neutral project management you can apply to any method.
View the ISO 21502 course →Questions
Is ISO 21502 a replacement for PMBOK or PRINCE2?
No — it's a vendor-neutral reference describing project-management practices. It complements PMBOK (a knowledge base) and PRINCE2 (a method) rather than replacing them.
Does it work with agile?
Yes — it describes practices without mandating a delivery approach, so it applies to predictive, agile, and hybrid projects alike.