Player identification number

A player identification number (often referred to as PID) is a unique identification number that each player possesses. It determines the priority between two or more players when simultaneously performing tasks throughout RuneScape.

Calculating
A random player I.D. is assigned to a player upon logging into the game, and it changes each time they log in. Prior to the player I.D. system, priority between players was based on the players' IP addresses.

Players can approximate their player I.D. by following a player and having them run. The delay between that other player moving and the player's character moving is believed to be caused by the player's player I.D. If the delay is longer than normal, the player has a higher player I.D. than the other player.

Examples of PID prioritisation
The following list contains examples of when a player I.D. becomes a factor in determining which player has the higher and lower priority.
 * PvM - Determines which player will deal the first hit of damage on a particular monster (and get the monster in single-way combat) when both players simultaneously attack the same monster.
 * PvP - Determines which player gets the first hit or when both players simultaneously attack each other at the beginning of combat.
 * Setting up barricades in various activities - Determines if another player can walk through a barricade that was just set up by another player.
 * Closing doors - Determines if a player can walk through a doorway while another player closes it at the same time.
 * "Catching" in RuneScape Classic - Player I.D. determines if a player can "catch" another player when player killing in the Wilderness. "Catching" is a RuneScape Classic term where after three rounds of combat, a player runs from their opponent, and the other player can "catch" them by chasing after them and attacking them again, bringing them back into combat.
 * Picking up items amongst other players - Affects which player gets an item if two or more players pick it up at the same time.