GTD is not hierarchical, in the sense that goals drive projects which drive actions. It acknowledges that goals and projects often emerge from actions. It also emphasizes feedback and flexibility, so goals and projects may be modified as circumstances change. I would characterize the idea of SMART goals, which in one version means specific, measurable, attainable, relevant and time-bound, as belonging to an earlier era of “time management“, and often associated with Peter Drucker’s concept of management by objectives. This doesn’t mean you can’t incorporate the criteria into GTD if you like. I don’t find them useful in my personal life, but I can see that they might be useful in corporate management. However, some of the examples I have seen of personal SMART goals are just silly. For example, “I will invest 5% of my income and retire at age 50” is probably just wishful thinking. It’s not really attainable, but our capacity for self-delusion can combine with a conviction we are “following the rules” to produce poor outcomes. Purpose, vision and goals are highly individual, and I don‘t believe there is a specific method to determine or record them that works for everyone in all circumstances.