The influence of refereeing experiences judging offside actions in football

In this study we assessed the influence of previous embodied refereeing experience on perceptual strategies used for judging offside events in football. For this purpose, 11 assistant referees and 11 players watched a video projected image of 24 offside sequences on a screen (5 x 3 m) in a laboratory. All participants, who were experienced in football at an amateur level, were required to decide when they perceived a player to be offside during observed sequences, viewed from an assistant referees perspective. An ASL SE5000 eye tracker was used to analyze participants' visual behaviours. Our interpretation of the results is that the specific previous officiating experiences of the assistant referees may have attuned their visual search strategies, such that they displayed a higher number of fixations and greater percentage viewing time on the last defender. In contrast, the players fixated for longer on areas of no interest. Despite these variations in visual search behaviours, no differences were detected in the percentages of correct offside decisions, yet differences did emerge in the incorrect decisions made. Specifically, the assistant referees achieved similar rates of false alarms and misses, and the players showed a bias towards calling offside when it was not offside. The assistant referees also missed more offside events and the players falsely flagged more events as offside in error. Further work is needed to clarify effects of these embodied officiating experiences in decision-making when participants with different experiences (e.g., player or match official) are asked to judge offside events in football.