Plan-driven and agile methods are completely different. They simply can't be combined because one forces you to do all of your planning up front and stick to it. The other requires you change as you go. So what makes one better than the other? What I discovered about this not only gave me peace of mind about many struggles I was having with the software process, but also changed the rest of my career. I went through about half of my career without knowing this. Fortunately, you don't have to wait that long.