Quantitative observations on object evolution

Our research starts to deal with the problems of how to proceed and manage incremental development of object-oriented software. When a system is developed incrementally, an application developer makes various design decisions. We have observed time series data of software development statistically and traced their quantitative characteristics. We have come to the conclusion that statistical analysis gives us two distinct development stages: the adding functions stage and the refactoring stage. This paper focuses on library class evolution processes.