The costs discussed are counted in development time, not the monetary value of rockets. That point is clearly evident with a cursory glance at the math. Just lo

The costs discussed are counted in development time, not the monetary value of rockets. That point is clearly evident with a cursory glance at the math. Just look at the numbers. The values all fall on the same curve. The cost increase from design phase to implementation phase is the same relative increase from implementation phase to testing phase, which is the same relative increase from the testing phase to the production phase. If it were counting the cost of rockets in the production phase, it would clearly jump that value off that cost curve in a dramatic and clearly notable way. The mathematical evidence of these facts is clearly visible in this chart: https://cdn-images-1.medium.com/max/2000/1*jOS7CZX-gWfOoKGPUU29kg.png https://cdn-images-1.medium.com/max/2000/1*jOS7CZX-gWfOoKGPU... Which is a reproduction of the graph that appears in the original paper using identical data. Of course, the data I cited was not the only data available on the economic impact of software quality. There is a whole chapter on the topic of the economic benefits of reducing bugs in the book "The Economics of Software Quality" by Capers Jones, Olivier Bonsignour Addison-Wesley, Jun 3, 2011. The book is packed with valuable references if you're looking for more data on why it's worthwhile to reduce production bug density using techniques like TDD and code review. I strongly suggest you have a look at it if you have any doubts about the value of reducing production bug density.