For those who do not know. IDPA stands for 'International Defensive Pistol Association'.
IDPA as a sport is quite simply the use of practical equipment including full charge service ammunition to solve simulated “real world” self-defense scenarios. Shooters competing in IDPA events are required to use practical handguns and holsters that are truly suitable for self-defense use. No “competition only” equipment is permitted in IDPA matches since the main goal is to test the skill and ability of an individual, not his equipment or gamesmanship. (Quote from http://www.idpa.com)