Leverage points: insights from a field study in the air traffic control systemLeverage points: insights from a field study in the air traffic control system Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2022-05-272021enAn important aspect of expertise is the ability of experts to notice ‘interesting events’ that provide opportunities for building efficient courses of action that make a significant impact on the operation of the system. These ‘interesting events’ are referred to as ‘leverage points’ that become the starting point in building new solutions to a problem. In this article, experienced controllers are observed in a series of simulation trials in order to record how leverage points are noticed and used in constructing new courses of action. A large number of scenarios were simulated and 10 controllers were employed to collect data about the use of leverage points. Quantitative results are presented on the types of leverage points used, their frequency of use and their likelihoods of failure. Based on the research results, a simple model has been proposed that relies on four cognitive processes that involve: noticing leverage points, building a curse of action, evaluating it and finally, repairing the course of action. Leverage points can be seen as the type of performance data that should be collected in the new Safety II approach to safety management.http://creativecommons.org/licenses/by/4.0/Theoretical Issues in Ergonomics Science223360–382 Malakis, Stathis Kontogiannis Thomas Κοντογιαννης Θωμας Taylor and Francis Group Leverage points Work practices Recognition-primed decisions Air traffic control Safety II