Software Peter principle

The conceptual integrity of software is a measure of how well it conforms to a single, simple set of design principles, according to The Mythical Man Month by Fred Brooks. When done properly, it provides the most functionality using the simplest idioms. It makes software easier to use by making it simple to create and learn.

Conceptual integrity is achieved when the software’s design proceeds from a small number of agreeing individuals. For software to maintain conceptual integrity, the design must be controlled by a single, small group of people who understand the code (including the nature of how all the subroutines and variables interact) in depth.

In projects without a strong software architecture team, the task of design is often combined with the task of implementation and is implicitly delegated among the individual software developers. Under these circumstances, developers are less likely to sacrifice personal interests in favor of the interests of the product. The complexity of the product grows as a result of developers adding new designs and altering earlier ones to reflect changes in fashion and individual taste.

Good software developers understand the importance of communicating with people over communicating with the computer, according to Code Complete by Steve McConnell. On average, 85 percent of a programmer's time is spent communicating with people, while only 15 percent is spent communicating with the computer. Maintenance programmers spend 50 to 60 percent of their time trying to understand the code they have to maintain and a software program will have, on average, 10 generations of maintenance programmers in its lifetime.

Programmers sometimes make implementation choices that work but have unintended negative consequences. The most common of these mistakes are cataloged and referred to as smells in the book Refactoring by Martin Fowler. Over time, many such implementation choices degrade the software’s design, making it increasingly difficult to understand.