@article {SAN17,
	title = {Empirical Study on Refactoring Large-scale Industrial Systems and Its Effects on Maintainability},
	journal = {Journal of Systems and Software},
	volume = {129},
	number = {C},
	year = {2017},
	month = {jul},
	pages = {107{\textendash}126},
	abstract = {We examine hundreds of manual refactoring commits from large-scale industrial systems.We study the effects of these commits on source code using a maintainability model.Developers preferred to fix concrete coding issues rather than fix code smells.A single refactoring had only a small impact (sometimes even negative effect).Whole refactoring process has significant beneficial effect on the maintainability. Software evolves continuously, it gets modified, enhanced, and new requirements always arise. If we do not spend time occasionally on improving our source code, its maintainability will inevitably decrease. The literature tells us that we can improve the maintainability of a software system by regularly refactoring it. But does refactoring really increase software maintainability? Can it happen that refactoring decreases the maintainability? Empirical studies show contradicting answers to these questions and there have been only a few studies which were performed in a large-scale, industrial context. In our paper, we assess these questions in an in vivo context, where we analyzed the source code and measured the maintainability of 6 large-scale, proprietary software systems in their manual refactoring phase. We analyzed 2.5 million lines of code and studied the effects on maintainability of 315 refactoring commits which fixed 1273 coding issues. We found that single refactorings only make a very little difference (sometimes even decrease maintainability), but a whole refactoring period, in general, can significantly increase maintainability, which can result not only in the local, but also in the global improvement of the code.},
	keywords = {Antipatterns, coding issues, ISO/IEC 25010, maintainability, refactoring, select:quality, software quality},
	issn = {0164-1212},
	doi = {10.1016/j.jss.2016.08.071},
	url = {http://www.sciencedirect.com/science/article/pii/S0164121216301558?via\%3Dihub},
	author = {Sz{\H o}ke, G{\'a}bor and Antal, G{\'a}bor and Csaba Nagy and Rudolf Ferenc and Tibor Gyim{\'o}thy}
}
@conference {SNF14,
	title = {A Case Study of Refactoring Large-Scale Industrial Systems to Efficiently Improve Source Code Quality},
	booktitle = {Proceedings of the 14th International Conference on Computational Science and Its Applications (ICCSA 2014)},
	series = {Lecture Notes in Computer Science (LNCS)},
	volume = {8583},
	year = {2014},
	month = {jun},
	pages = {524{\textendash}540},
	publisher = {Springer-Verlag},
	organization = {Springer-Verlag},
	address = {Guimar{\~a}es, Portugal},
	abstract = {Refactoring source code has many benefits (e.g. improving maintainability, robustness and source code quality), but it takes time away from other implementation tasks, resulting in developers neglecting refactoring steps during the development process. But what happens when they know that the quality of their source code needs to be improved and they can get the extra time and money to refactor the code? What will they do? What will they consider the most important for improving source code quality? What sort of issues will they address first or last and how will they solve them? In our paper, we look for answers to these questions in a case study of refactoring large-scale industrial systems where developers participated in a project to improve the quality of their software systems. We collected empirical data of over a thousand refactoring patches for 5 systems with over 5 million lines of code in total, and we found that developers really optimized the refactoring process to significantly improve the quality of these systems.},
	keywords = {refactoring, Software engineering, software quality},
	doi = {10.1007/978-3-319-09156-3_37},
	url = {https://link.springer.com/chapter/10.1007\%2F978-3-319-09156-3_37},
	author = {Sz{\H o}ke, G{\'a}bor and Csaba Nagy and Rudolf Ferenc and Tibor Gyim{\'o}thy}
}
