What expected threat measures
Expected threat, usually written xT, assigns every zone of a football pitch a value equal to the probability that possession in that zone leads to a goal within the next few actions. The pitch is divided into a grid, commonly 16 by 12 cells, and each cell carries a single number between 0 and 1. Zones near the opponent's goal carry the highest values; zones in a team's own defensive third carry values close to zero.
The model works by combining two things for each cell: the chance of shooting from that cell and scoring, and the chance of moving the ball to a more dangerous cell on the next action. Solved iteratively, this captures not just where shots happen but where valuable build-up play happens, which is why a pass into the half-space can be credited even though no shot immediately follows.
How it differs from expected goals
Expected goals (xG) values a single shot. Expected threat values possession of the ball in a location, so it credits passes, carries, and dribbles that move the ball into more dangerous areas. A line-breaking pass that raises the threat value of the receiving zone earns positive xT even if the move ends without a shot, making xT a natural tool for evaluating progressive passers and ball carriers rather than only finishers.
Reading the map
Darker or warmer cells mark higher threat. The gradient typically rises smoothly toward the goal and bulges in the central channels and half-spaces, the areas from which scoring chances most often originate. Analysts use the difference in xT between the start and end zone of an action to quantify how much danger a single pass or carry added, then sum those deltas per player to rank ball progression over a match or season.