Impact analysis plays an important role in many software engineering tasks such as software maintenance, regression testing and debugging. In this paper, we present a static method to compute the impact sets of particular program points. For large programs, this method is more effective than the slightly more precise slicing. Our technique can also be used on larger programs with over thousands of lines of code where no slicers can be applied since the determination of the program dependence graphs, which are the bases of slicing, is an especially expensive task. As a result, our method could be efficiently used in the field of impact analysis
