# Quantifying Football Shooting Precision: The Expected Shot Impact Timing (xSIT) Approach
## 6 Discussion of the Model  
The xSIT model proposed in this study aims to provide a more accurate evaluation of shooter performance in shooting situations. This model was developed based on a large-scale dataset comprising high-resolution positional and event data, systematically captured and accurately synchronized using a proprietary algorithm. In contrast to prior models [20,21], which often obscure the underlying computational processes and report only aggregate outputs, our approach was characterized by full methodological transparency. Specifically, we provided a detailed account of the input variables and the step-by-step procedures involved in the calculation of each metric. This level of detail facilitated a more nuanced interpretation of player performance, particularly in evaluating the contextual factors that influence the effectiveness of a shot. Such transparency not only enhances the model's interpretability but also allows for its application in both talent identification and individualized performance optimization. For instance, targeted training interventions, such as drills aimed at enhancing moment reaction and positional adaptability in both GKs and defenders, could effectively reduce xSIT values, thereby reflecting improved anticipatory behavior and spatial control. Similarly, exposing strikers to high-pressure shooting scenarios involving dynamic obstacles can refine technical execution and decision making under stress, ultimately contributing to increased offensive efficiency. The findings derived from the present study (Figure 9) suggested that the xSIT metric complements other advanced metrics like xGOT by incorporating not only shot characteristics but also key variables related to ball velocity and player reaction times. The xGOT focuses on assessing the GK's movement time, that is, the time interval between the execution of the shot and the moment the GK is able to attempt to stop the ball [5,7,8,22]. The xGOT accounts for factors such as the distance between the GK and the ball's trajectory and positioning. The xSIT assesses the ball velocity and the reaction times of both the GK and outfield players in response to the shot. This metric evaluates the ability of all involved players to anticipate and react to the shot, including the potential for outfield players to block, intercept, or deflect the ball before it reaches the goal. In this sense, xSIT provides a more comprehensive view of reaction time during shot situations, taking into account not only the GK's skill but also the collective defensive response. Through this approach, an integrated assessment was provided, taking into account both the conditions of the shot and the context in which it occurs. One of the main advances of the xSIT model was the inclusion of ball velocity and player reaction times, two factors that have generally been overlooked in previous shot analysis models. Other advanced metrics, such as xG, typically focus on pre-shot characteristics, such as distance, angle, and the initial speed of the shot, without considering the impact of the shooter's technical quality or the GK's and outfield players' reactions [3,4]. However, the xSIT model adds an additional layer of complexity by integrating how quickly players react, which can alter the likelihood of a shot resulting in a goal. This makes the model a more precise tool for evaluating shooter performance in dynamic situations. Figure 10: Gender-based comparison of the xSIT metric between the two tournaments. An additional strength of this study lies in the inclusion of match data from both elite men's and women's international tournaments. This approach enabled the exploration of potential gender differences in the application of the xSIT metric to men's and women's football. As shown in Figure 10, the results revealed lower xSIT values for women players compared to their male counterparts.