It pays to plan. Entrepreneurs who write business plans are more likely to succeed, according to our research, described in an earlier piece for Harvard Business Review. But while this might tempt some entrepreneurs to make writing a plan their very first task, our subsequent study shows that writing a plan first is a really bad idea. It is much better to wait, not to devote too much time to writing the plan, and, crucially, to synchronize the plan with other key startup activities.