I am interesting in finding out if there are any examples of large legacy projects that have gone through a "successful" quality improvement process. By success I mean a step change in quality.

• Large: greater than 1MLOC
• Legacy: no automated tests
• Poor quality: high complexity, high coupling, high escaped defects

The reason I find this interesting is that there is a lot of information about tools and techniques for improving large legacy codebases, but I haven't come across any real world case studies. I think that this information would be very motivating for developers and managers in this situation.