@proceedings {1501,
	title = {The Impact of Tangled Code Changes},
	year = {2013},
	month = {05/2013},
	abstract = {When interacting with version control systems, developers often commit unrelated or loosely related code changes
in a single transaction. When analyzing the version history, such
tangled changes will make all changes to all modules appear
related, possibly compromising the resulting analyses through
noise and bias. In an investigation of five open-source JAVA
projects, we found up to 15\% of all bug fixes to consist of multiple
tangled changes. Using a multi-predictor approach to untangle
changes, we show that on average at least 16.6\% of all source
files are incorrectly associated with bug reports. We recommend
better change organization to limit the impact of tangled changes.},
	keywords = {bias, data quality, history, java, mining software repositories, noise, tangled code changes, version control},
	url = {http://www.kim-herzig.de/wp-content/uploads/2013/03/msr2013-untangling.pdf},
	attachments = {https://flosshub.org/sites/flosshub.org/files/msr2013-untangling.pdf},
	author = {Kim Herzig and Zeller, Andreas}
}
@proceedings {1521,
	title = {It{\textquoteright}s Not a Bug, It{\textquoteright}s a Feature: How Misclassification Impacts Bug Prediction},
	year = {2013},
	month = {05/2013},
	pages = {392-401},
	abstract = {In a manual examination of more than 7,000 issue reports from the bug databases of five open-source projects, we found 33.8\% of all bug reports to be misclassified{\textemdash}that is, rather than referring to a code fix, they resulted in a new feature, an update to documentation, or an internal refactoring. This misclassification introduces bias in bug prediction models, confusing bugs and features: On average, 39\% of files marked as defective actually never had a bug. We discuss the impact of this misclassification on earlier studies and recommend manual data validation for future studies.},
	keywords = {bias, bug reports, data quality, mining software repositories, noise},
	author = {Kim Herzig and Sascha Just and Zeller, Andreas}
}
