What kind of and how clones are refactored?

Although code clone (i.e. a code fragment that has similar or identical fragments) is regarded as one of the most typical bad smells, tools for identification of clone refactoring (i.e. merge code clones into a single method) are not commonly used. To promote the development of more widely-used tools for clone refactoring, we present an investigation of actual clone refactorings performed in the developments of three Open Source Software (OSS) projects. From the results, we confirmed that clone refactorings are mostly archived by two refactoring patterns, and token sequences of refactored code clones are suggested to have a difference of 50%.