A virtuous circle is one where a recurring cycle of events in one event increasing the beneficial effect of the next. In systems terms, a virtuous cycle is a reinforcing loop which produces desirable behavior.
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[1] https://managingresearchlibrary.org/knowledge/blog/lexicon
[2] https://managingresearchlibrary.org/about
[3] https://managingresearchlibrary.org/glossary/causal-loop-diagram
[4] https://managingresearchlibrary.org/glossary/virtuous-cycle
[5] https://managingresearchlibrary.org/glossary/vicious-circle