Writing a business within the first six months of launching a business is not worthwhile and may even be counterproductive, according to research by the University of Edinburgh Business School that is based on a study of more than 1,000 US entrepreneurs over a six-month period from 2005 to 2011.

Instead, the key to starting a successful business is being flexible and responsive to opportunities. It’s not having a rigid plan.

“Our research 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 it, and, crucially, to synchronize the plan with other key startup activities,” said Professor Francis Greene, a co-author of the report.

“Writing a plan between six months to a year increased the probability of venture viability success by 8% — but writing one earlier or later than this proved to have no distinguishable impact on future success,” Greene said.

Those starting businesses often have to adapt their business dramatically once it becomes clear what their target market is, making the writing of a plan early on a waste of time.

The optimal length of time to spend writing a plan was found to be three months. Spending longer does not help because the information in the plan becomes less current.