I appreciate that Ousterhout tries to support these principles with some data from his own experience (building Tcl, RamCloud where Raft consensus was discovered, etc) and from code reviews of student projects in his design course, but he admits that there is a lack of data about things like design.
Sample principles from Ousterhout:
* When developing an interface, favor exposing a small number of functions each with deep functionality over exposing a large number of functions each with shallow functionality. For example, favor Unix file I/O interface (open, close, read, write, unlink) over Java file I/O interface (File, FileReader, BufferedReader, FileWriter, BufferedWriter, FileNotFoundException, ... etc.)
* When choosing between keeping your code specific and keeping your code general, favor "somewhat" general. For example, instead of exposing "deleteNextCharacter(text, pos), deleteNextWord(text, pos), deleteNextSentence(text, pos)", just expose "delete(text, pos, length)" and let the caller use it how they will.