Valve has confirmed that it is focusing on addressing problems with the hitboxes in Counter-Strike: Global Offensive. Three years after the game originally released, Valve took notice of complaints regarding hitboxes after a thread on Reddit highlighted the broken nature of the hit detection.
You can see the hit detection problem in GIF form at http://gfycat.com/UnlinedCavernousDesertpupfish where he clearly shoots the bomb planter but doesn’t register and instead gets killed by the enemy player.
Hitboxes are invisible when playing games but in a game editor show as a boundary box around your player character. When you move, the hitbox follows and to account for Internet latency can sometimes be in front or behind the actual character model as seen in blue and red in the image, this is sometimes known as lag compensation. When shooting, the hitbox is what registers the hit and any animations and health loss are triggered.
One of the Redditors emailed Valve regarding the issue and obtained a response from Valve’s Matt Wood saying, “It’s being worked on. We don’t have an eta.”
Hitboxes aren’t limited to being a Counter-Strike: Global Offensive issue, Battlefield and Call of Duty have also had their fair share of issues throughout their respective franchises.