Real Figures
- 57% of projects fail due to poor project scoping
- 35% fail due to buggy software
- 30% fail due to unattainable business requirements.
Change Is Inevitable
- In 1997 Jones found that medium to large projects experience 25-35% change
- In 1998, Reinerston discovered that out of over 80 projects analysed,there was no case for which requirements remained stable
- Boehm & Papiccio in 1998 observed that a typical project experiences a 25% change in requirements
To put this into some perspective, a 6 month project costing £500,000, will typically either overrun by 31 days, and waste £125,000 in unwanted features, and cost an additional £125,000 in new functionality.
Realities of Software Development
- Requirements change
- Customers never knows exactly what they need
- Requirements are rarely complete and/or 100% signed off by all participants
- People rarely understand requirements from the beginning
- People make mistakes but it’s hard to fix them on the latter stages of development
- For most, it is hard to successfully design everything in advance
- Up-front design is too much and very expensive