Why large projects Fail

There are many reasons why large projects fail. Here are just some of them

1. There is too much optimism as to the potential benefits the proposed system ... and to the cost of delivering those benefits 
2. There is too little investment at the beginning ...
3. If sufficient investment is made eventually, it is too late ... so we lose even more money
4. There is not enough technical know-how in the project team. 
5. There are opposing human factors aspects - including insufficient consideration of team working, project management and risks. 
6. The project does not plan incremental roll-out and fails to anticipate the effect of big-bang on the organisation. 
7. (for IT project) The project tries to match IT to the existing Business Processes of the organisation, rather than mandating that the Business Processes change to match those easily supprted by the IT. 
8. Initial under-investment leads to an investment legacy, where the project has invested in bad decisions and doesn't have the courage to retreat. 
9. There are many management disaster scenarios that can be to blame, such as 
10. the parent/child governance scenario, where authority within the project remains with senior management in the customer. 
11. the enthusiastic builder scenario, where the supplier has a vested interest in prolonging the project since payment is related to time-on-the-job rather than delivery of results. 
12. And of course, because of insufficient planning and because the project takes a long time from inception to completion, there is a requirements explosion during the lifetime of the project ... which means that what is eventually required is significantly different from what was originally anticipated