A large-scale empirical study of practitioners´ use of object-oriented concepts

We present the first results from a survey carried out over the second quarter of 2009 examining how theories in object-oriented design are understood and used by software developers. We collected 3785 responses from software developers world-wide, which we believe is the largest survey of its kind. We targeted the use of encapsulation, class size as measured by number of methods, and depth of a class in the inheritance hierarchy. We found that, while overall practitioners followed advice on encapsulation, there was some variation of adherence to it. For class size and depth there was substantially less agreement with expert advice. In addition, inconsistencies were found within the use and perception of object-oriented concepts within the investigated group of developers. The results of this survey has deep reaching consequences for both practitioners and researchers as they highlight and confirm central issues.