PRINCE2 principles
What the principles are
PRINCE2's seven principles are the enduring, universal reasons why the method works: continued business justification, learn from experience, defined roles and responsibilities, manage by stages, manage by exception, focus on products and tailor to suit the project context. They are the 'why'; the practices and processes are the 'what' and 'how'.
What a candidate must understand
Principles are never optional and are never tailored away - tailoring changes processes, products and roles, never principles. Every project must be able to evidence all seven, even if lightly. Learn from experience is continuous: the lessons log starts in starting up a project and lessons must be applied, not merely recorded. Manage by stages creates staged control with the project board authorising each stage; manage by exception sets tolerances so the board is involved only when limits are threatened. Focus on products means defining and controlling outputs, their quality criteria and acceptance, rather than managing activities. Defined roles and responsibilities means clear accountability, not a fixed organisation chart.
Traps
Common distractors describe sensible project activity that is not a PRINCE2 principle (for example 'deliver on time and budget', 'keep a risk register'). Others swap manage by stages with manage by exception, or suggest principles can be dropped on small projects. Watch for options claiming a principle can be 'streamlined' - the activity may be simplified, but the principle remains.
Worked example / rule of thumb
A six-week internal website refresh: the team proposes skipping a business case as 'too heavy'. The correct answer is to keep continued business justification in a simplified one-page form - activity scaled, principle kept. Rule of thumb: if a proposed tailoring removes or contradicts a principle, it is wrong.