The effect of inheritance on the maintainability of object-oriented software: an empirical study

The empirical study was undertaken as part of a programme of research to explore unsupported claims about the object-oriented paradigm: a series of experiments tested the effect of inheritance on the maintainability of object-oriented software. Subjects were asked to modify object-oriented software with a hierarchy of 3 levels of inheritance depth and equivalent object-based software with no inheritance. The collected timing data showed that subjects maintaining object-oriented software using inheritance performed the modification tasks, on average, approximately 20% quicker than those maintaining equivalent object-based software with no inheritance. An initial inductive analysis revealed that 2 out of 3 subjects performed faster when maintaining the object-oriented software with inheritance. The findings are sufficiently important that attempts to verify the results should be made by independent researchers. Subsequent studies should seek to scale up the findings to the maintenance of more complex software by professional programmers