Heading the list were lack of user input into the planning process and incomplete and changing requirements and specifications. If carefully defined, these requirements and specifications should guide and control the project. If properly incorporated into the legal contract with the vendor, they also become legally binding incentives and baselines to measure vendor performance. However, if poorly planned, the user loses control over the project and probably won't get what it wants. Unfortunately, vendors sometimes oversell their capabilities.
Vendors compete fiercely to establish market share and industry standards.
Marketing personnel often commit to performance features and delivery dates without fully involving the vendor's development organization. More commonly, there is merely an honest disconnect between what the user truly needs and expects and what the vendor can truly deliver. These problems are exacerbated by the typical rush to complete the project. Post-development training support and maintenance, which are critical to overall project success, are frequently disconnected from the development process. In many failures, the user is left with little recourse.