A surprisingly high number of projects are 'ticking time bombs', according to researchers at the University of Oxford. They analysed 1,500 global projects that had revamped their information technology systems within the last 10 years. They discovered that one in six projects in the sample went over budget by an average of 200 per cent (in real terms) or over ran by an average of almost 70 per cent.
Their conclusion is similar to previous studies: http://brunovernay.blogspot.com/2009/10/excellent-studies-on-software-quality.html