We motivate and describe why erosion modelingfrom a static architecture conformance checking point of view isimportant as well as the impact we think it can have on industry.Our research goal is to get a better understanding of erosionand develop smarter and simpler methods to assess erosion. Wedescribe preliminary results from a retrospective, longitudinalcase study of an open source software. The software system westudy, JabRef, was created in 2003, and refactored to a layeredstructure to “transition from a spaghetti to a more structuredarchitecture” in 2015. We construct a model from this new,layered architecture, and assess 30 versions of JabRef to findarchitectural conformance violations. Our preliminary resultsshow a significant difference in productivity after refactoring andsuggest that there is a connection between our model of erosionand productivity where more erosion gives lower productivity.