Ratio between weekly number of changes and weekly number of changed concepts in our five collaborative ontology engineering projects NCIt, ICD-11, ICTM, OPL, BRO, and in Wikipedia ICD-10 (as control). Note that the x-axis is scaled differently for each project due to differences in the change log durations. The inset for Wikipedia ICD-10 magnifies the reatio for a period of 52 weeks (one year) to highlight seasonal fluctuations.