Summary from the introduction: What useful information can be learned from the 600+ datasets analyzed in this book? There are a few high-level take-aways from

Summary from the introduction: What useful information can be learned from the 600+ datasets analyzed in this book? There are a few high-level take-aways from the recurring patterns seen in the analysis; these include: - there is little or no evidence for many existing theories of software engineering, - most software has a relatively short lifetime, e.g., source code is deleted, packages are withdrawn or replaced, and software systems cease to be supported. A cost/benefit analysis of an investment intended to reduce future development costs needs to include the possibility that there is no future development; Changes within the ecosystems in which software is built also has an impact on the viability of existing code; - software developers should not be expected to behave according to this or that mathematical ideal. People come bundled with the collection of cognitive abilities and predilections that enabled their ancestors, nearly all of whom lived in stone-age communities, to reproduce;