Get Your Goals Back on Track – Heidi Grant Halvorson – The Conversation – Harvard Business Review

I think it’s important to distinguish between specificity and inflexibility. While I can’t think of a single study where specificity hurt performance, I can think of many where a dogged insistence on staying the original course proved harmful. People need to be able to respond to changing conditions. So one qualification might be “clarity is helpful when it does not rule out flexibility and responsiveness.” 

Second, I think a lack of specificity at the organizational level isn’t quite the same thing as a lack at the individual level. Even in the instances you mentioned, the individual employees probably had some specific shorter-term goals they set for themselves. If you are trying out different strategies and exploring possibilities, you still benefit from having a clear idea what “successful” looks like, so you’ll know when a strategy is promising and when to switch to something else.