Expected Threat (xT) is calculated by laying a 'value surface' over a football pitch to divide it into zones, where each zone has a value assigned to it based on how likely a goal is to be scored from that zone. Players can then be credited for moving the ball from zone to zone. It was first introduced by Karun Singh in 2018, and is arguably the most known possession value model in the industry. However, it only values actions that move the ball from zone to zone, such as passes and carries, excluding defensive actions and shots. It is also typically implemented on limited event data, ignoring factors such as whether the player was under pressure or not when making the action.