How is the speed of code review affected by activity, usage and code quality?

Abstract: This paper investigates how the speed of code review is affected by the code quality, activity and usage in the context of MediaWiki extensions. The median time to merge is compared against several other variables which are collected using a variety of manual methods and APIs. The results are graphed where possible and statistical analysis is used to determine the significance of the results. The paper finds that the number of reviewers voting on code and whether the extension has a steward affects the median time to merge. Finally, conclusions are drawn and further research topics are recommended.