Expected Threat (xT)
Expected threat divides the pitch into zones, assigns each a value equal to the chance that the team in possession scores from there before losing the ball, and values an action by the rise in that value.
What it means
Zone values are estimated by working backwards from goals through the chains of moves that produced them. An action that moves the ball from a low-value zone to a high-value one adds the difference in threat.
Why it matters
It values passing and carrying in midfield, which goal-based and assist-based metrics ignore, so build-up players acquire a measurable contribution that other statistics miss.
Where it is used
Analysis of deep midfielders, ball-playing defenders and any question about the value of progression rather than the value of chances.
Where it misleads
It is blind to defenders, marking and the identity of the player, so two passes to identical coordinates receive identical credit. It also assumes the value of a position is independent of how the ball arrived.
Key points
- It needs only coordinates, so it can be computed for old and un-tracked competitions.
- Values rise steeply towards the goal and towards the centre.
- Never add expected threat to expected goals; they measure different objects.
- Report threat per ninety minutes alongside the action count.
- Grid resolution trades detail against stability and must be stated.
- High threat with low expected goals describes circulation without penetration.
Expected threat is the best available answer to what a pass is worth when nobody shoots, which is most of the time in most matches.