Identification of software instabilities
Jennifer L. Bevan, E. James Whitehead · 2004
As software evolves, maintenance practices require a process of accommodating changing requirements while minimizing the cost of implementing those changes. Over time, incompatibilities between design assumptions and the operational environment become more pronounced, requiring some regions of the implementation to require repeated modification. These regions are considered to be "unstable", and may benefit from targeted restructuring efforts as a means of realigning these assumptions and the environment.