Next, we turn to the benefits. If you can show that the improvement will pay for itself, then the other benefits would be pure gravy. So start by making the cost case. The way to make the cost case is to first gather the available facts on improvement benefits. Here, you are at a disadvantage.
Costs are always easier to prove than savings.
Executives know this, however, probably better than you do. After all, they spend much of their time justifying changes. But they will want a logical story that hangs together and looks complete and realistic. Unfortunately, there are few statistically sound improvement studies, even for accepted process-improvement methods. While there may be some available analyses, you will probably have to rely on anecdotal evidence.