| It typically takes 15% of the total project time to define the product including requirements | Wiegers and Beatty, 2013, Software Requirements – Third Edition, Microsoft Press |
| It can cost as much as 10-20 times more to change a requirement once it has been developed. | Wiegers and Beatty, 2013, Software Requirements – Third Edition, Microsoft Press |
| Product definition and requirements defects is often accountable for more than 50% of project rework | Wiegers and Beatty, 2013, Software Requirements – Third Edition, Microsoft Press |
| 20% of features are used often50% of features are hardly ever or never used. | CHAOS Manifesto, 2013, The Standish Group) |
| Studies show that lack of user involvement is a main factor (15% of the cases) in projects that fail. ref (Chaos manifesto, 2013) | CHAOS Manifesto, 2013, The Standish Group) |
| There are surveys indicating that non-functional tasks including testing often takes up more than 50% of total time in projects and up to 65% in big projects | Jones, 2007, Estimating Software Costs, Bringing realism to estimating, Mc Graw Hill |
| There is rarely full overview of requirements when product development is started. Often only 50% of the requirements are known | Jones, 2007, Estimating Software Costs, Mc Graw Hill |
| Surveys suggest that a rough average of 20% of requirements are delayed to later releases in software projects | Jones, 2007, Estimating Software Costs, Mc Graw Hill |
| Typically there is a 2% growth rate in requirements in software projects per calendar month | Jones, 2007, Estimating Software Costs, Mc Graw Hill |