Effects of Software Changes on Module Cohesion

W e use program slices to model module cohesion. For our purposes, a slice is a projection of program text that includes only the data tokens relevant t o one output. W e define six cohesion metrics in terms of these slices, and evaluate the effects of classes of module changes on these metrics. W e find that the effects on cohesion metrics are notably more predictable when the changes result from adding code rather than from moving code. In general, the effects that software changes have on the cohesion metrics match our intuition.