Semi-automated offside technology (SAOT) is a support tool that helps video assistant referees (VARs) to make faster, more reproducible and more accurate offside decisions. Advanced SAOT uses the same system but additionally sends information directly to the on-field match officials for clear offsides to further speed up the decision-making process.
With the introduction of video assistant refereeing, it became possible to assess offside situations that previously would not have been checked in real time. Because of the complexity of determining whether a player is on- or offside, for which it is necessary to consider both the exact time when the ball is played and the positions of the second-to-last defending player and the attacking player receiving the ball, a technology-driven solution was sought to support the decision-making process by providing these pieces of information to the VARs automatically. Another issue was that, following the advent of video assistant refereeing, assistant referees were instructed to delay raising their flags in offside scenarios when there was an immediate potential goalscoring opportunity, in order to prevent play from being stopped for offside (and thus avoid denying goalscoring opportunities) when the player in question was actually onside. However, allowing the action to continue for lengthy periods can lead to avoidable injuries in situations when the play is then brought back for offside anyway. Such risks are averted by delivering objective, real-time offside information directly to the on-field officials for clear offsides. FIFA’s system uses 16 dedicated cameras mounted inside the stadium to track the positions of the ball and players, typically 50 times per second. For each player, 29 data points are collected during each frame, including all body parts that are relevant for making offside calls. Ball data is collected via optical tracking and, where available, the sensor from connected ball technology to complete the dataset. For SAOT, the combination of limb and ball tracking data then allows the technology to provide automated offside alerts to the VARs inside the video operation room, whenever the ball is received by an attacking player who was in an offside position at the moment when the ball was played by a team-mate. The VARs can review the proposed decision before it is communicated to the on-field officials.
Advanced SAOT does all the above but also sends an audio signal directly to the on-field officials for clear positional offsides, allowing them to make instant decisions. The logic of the system was developed by the Football Technology Centre, a joint venture between FIFA and Hawk-Eye Innovations. For both SAOT and advanced SAOT, once the decision is confirmed, a three-dimensional animation is generated based on exactly the same positional data points that were used to make the decision to illustrate the outcome to fans on television and, where applicable, to the crowd on stadium screens. The SAOT set-up and workflow were initially trialled in several tournaments prior to full introduction at the FIFA World Cup 2022. Advanced SAOT was tested at various FIFA tournaments before the FIFA World Cup 2026 including the FIFA Club World Cup and the FIFA Intercontinental Cup in 2025. Following the approval of a test methodology for advanced SAOT through the FIFA Quality Programme for Offside Technology’s Technical Advisory Group, the system has been independently validated in use.
Source: FIFA
