How often do you join a project and find that the documentation tells you all you want to know? Yep - never works completely for me, either. In "Your Crucial - and Unwritten - Plan" (Linda Hill & Kent Lineback - Harvard Business Review) the authors give one important reason for this - our written plans are rapidly supplemented or superceded by a constantly evolving unwritten plan. It' not just that most of us don't make the time to update our written plans at every twist and turn - the unwritten plan is a different beast altogether:
In sum, a written plan covers only those portions of your thinking that are clear, specific, focused, thought-through, and ready to go public as a formal (and often official) document bearing the title "Plan." Unwritten plans consist of your and your group's thoughts — ranging from vague hunches to roughly-written ideas — about the future and how all of you will create it. Formal, written plans are prepared at key points, while unwritten plans are living, dynamic possibilities that constantly change as you learn more from experience and carry on discussions with your people and network.
(From Your Crucial - and Unwritten - Plan (Linda Hill & Kent Lineback - Harvard Business Review, 10 May 2011)
In that case, I was thinking, a key point is to take time to review and evaluate your own unwritten plan. Writing the darned thing down, while time-consuming, might help - it allows you and others to critique it, and allows one to step back from it. The unwritten plan can readily become one that is obsessed by the next milestone, or fatally discounts a certain risk or suffers from other forms of myopia. But a periodic write-up may not be the whole solution - vague feelings of unease about something can be too nebulous or personal to put into a formal plan (especially if it is to be shared), but can be a really useful indication of trouble ahead. Time out to think about things seems the only way to review the unwritten plan - hard to achieve in today's busy working lives (I used to find my cycle ride to work or a lunchtime walk very useful for this).