How well do experienced software developers predict software change?

Requirements-driven impact analysis (RDIA) identifies the set of software entities needed to be changed to implement a new requirement in an existing system. The input is a set of requirements and the existing system. The output is, for each requirement, a set of software entities that have to be changed. The output is used as input to many project-planning activities, for example cost estimation based on change volume. This paper quantifies how well experienced software developers predict change by conducting RDIA, where RDIA in this case is the general activity of predicting changes based on change request. The means has been an empirical study of RDIA in the industrial object-oriented PMR-Project. RDIA has been carried out in two releases, R4 and R6, of this project as a normal part of project developers' work. This in-depth case-study has been carried out over four years and in close contact with project developers. The correctness of the prediction is high while problems with underprediction have been identified many more classes than predicted are changed. We have also found that project developers are unaware of their own positive and negative capabilities in predicting change. (C) 1998 Elsevier Science Inc. All rights reserved.