nterest in the potential of improvisation to enhance safety outcomes in safety critical situations has been increasing; however, improvisation also has the potential to make emergency situations worse rather than better. If organisations are to capitalise on improvisation s potential to produce safety benefits, a model of the factors that influence its effectiveness in safety critical situations is needed. This review draws together what is currently known about the factors influencing improvisation and the methods used to examine them. The review reveals that, unlike most contemporary ergonomics concepts, as yet no research has examined factors beyond organisational boundaries or examined the interactions of factors across different systems levels, both integral components of systems-based models. In closing, discussion is presented on the most appropriate research agenda for enhancing understanding of improvisation and its influencing factors.