There are many statistics on the validity of sharply defined market requirement documents, including the following quote from Robert G. Cooper in Winning at New Products,

Successful products have much sharper definition prior to development. Projects that have these sharp definitions are:

  • 3.3 times as likely to be successful
  • Have higher market share
  • Are rated 7.6 out of 10.0 in terms of profitability (vs. 3.1 out of 10.0 for poorly defined projects)

Few technology companies know their markets. It is not that software and hardware companies ignore their customers; in many cases they have reams of customer input from sales, customer service and user groups that product managers sift through to develop lengthy lists of product and feature requirements. But there are some key differences in the methodology used to determine product and release drivers […]

source: pragmaticmarketing.com