Is the PMBOK® Guide descriptive?
It's commonly said that PRINCE2® is prescriptive, while the PMBOK Guide is descriptive. I don't think so, though.
Both PRINCE2 and the PMBOK Guide are telling people what actions are correlated with success. One frames it as, "Do ###, if you want to be successful", while the other says, "Successful projects do ###" and implies that, "You probably want to do the same".
These are two sides of the same coin. A truly descriptive resource can only help people understand what's going on in projects (like the way a dictionary helps you understand how words are used); but what people expect from resources is that they help them understand what can increase their chances of success (like a grammar book).
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