When people play online First Person Shooters, there are often arguments over the various advantages and disadvantages of ping imbalance.  Players get killed after they dodge around corners and argue that they would have made it to safety if their opponent had lower ping.  I want to try and set the record as straight as I can here by explaining what is really going on and who actually has the advantage.  The reality is that in most cases play style decides who gets the biggest advantage, although high pingers do have at least one distinct disadvantage.

I'll explain the reason why toward the bottom of this page, but first I want to explain what actions you should and should not take in match-ups where pings are high enough.  So try to keep this stuff in mind if <your ping + your opponent's ping> is greater than 150ms, as it applies to both people.

Generalizations/key takeaways

In situations where the opponent must react to your actions, then you've found a situation where you can use what is often referred to as "Peeker's advantage" (even if it isn't a peek).  Example: You literally peek around the corner, see your opponent standing still or walking in a straight line, snipe him, then duck away behind cover.  Or you change from a projectile weapon to hitscan weapon (or vice versa) in the middle of a fight and get an easy shot off because your opponent was still dodging as if you were holding out a weapon where he was forced to dodge differently.  

If you can think of a situation where you are waiting for your opponent to do something before you act, you would be putting yourself at a disadvantage by doing so in a high ping vs low ping game.  Don't sit around and wait for your opponent.  Peek around every corner you safely can to see if you can get free damage off before your opponent knows he has to dodge.  Don't waffle between two choices of which direction to go, be decisive.  Aggression works out more often than it would on LAN, and waiting for engagements works out less often online.

If you must wait in one place, always spam movement keys as if you are dodging an opponent who is already aiming at you.  Never stand still, and try not to walk in straight lines, because your opponent could be aiming at you before you know he is.

Real world example of Peeker's Advantage in QPL NA Challenger League:
Dooi and Steej come up to the same corner.  Dooi peeks the corner, fires a rocket, and runs away before Steej can even return fire.  Steej's screen probably even had his position jump when the server said "a rocket knocked you over here" so he had to wait a little longer for his view to update before he could fire a shot, otherwise he would have shot in the wrong direction.

Steej could have gotten his shot off first if he'd peeked, but Dooi also could have returned fire since his ping was lower.

Explanation of why

First, I want to make sure everyone understands the basics - ping is the time it takes for a message from one computer to go to another computer and back.  If you have 50ms ping in a game, it takes 0.050 seconds for your actions to be sent to the server and the server to reply with a confirmation that you did what you think you did.  In some of the first online FPSs, that delay actually applied between you pressing a movement key and seeing it happen.  It didn't take long for game clients to start predicting movement locally, but a few more years passed before shots had lag compensation (before this improvement in games, you had to aim ahead of your target based on ping - even with hitscan weapons).  However, there is no way to make your actions show up on your opponent's screen at the same time as it did on your screen.

The magic of lag compensation can take a few forms, but the end result is all that we really care about.  Hitting your target just depends on what it looked like on your screen.  Likewise, whether your opponent hit you or not depends on what it looked like on HIS screen.  See this clip as a real world example.  So let's talk about the consequences of this while keeping in mind that your position on your screen is not where your opponent sees you at that moment in time.

  1. The most common complaint, "I ran behind cover and died after I was out of line of sight," happens because on your opponent's screen you started to run for cover, but he killed you before you got there.  The period of time where you got behind cover was a lie, and you were already dead.  But this happens both ways!  If you see a high pinger running for cover and kill him, he probably saw himself get out of harm's way before he abruptly died.  In reality, this is neither an advantage nor a disadvantage - it's just an annoyance until you can consciously recognize that you can't trust your game client's view of being alive until after you see your opponent's shot missed.  If both of you had lower pings in such a situation, the difference is that the victim would have seen himself die before getting behind cover.
  2. In games where there is knockback on weapon damage, people with higher pings do have a legitimate disadvantage that only affects them.  Keep in mind that the guy with high ping sees himself ahead of where the server does, and when the server says "this explosion bounced you here" then the server is calculating it from a different position than the high pinger thought he was at, which means that the high pinger's view suddenly jerks to where the server thinks he should be.  If this sudden shift in position happens just as the high pinger is trying to shoot, then he very easily could miss shots that would have been hits on lower ping.
  3. Finally, let's talk about the real advantage that exists: Peeker's advantage.  The most important thing to understand about this is that it applies to BOTH players (the low pinger, and the high pinger), but as stated above you must alter your behaviors to minimize your opponent's advantage and take advantage of it yourself.  On both player's screens opponents' movements are effectively delayed by the same amount, and the players are shooting at an outdated version of each other.  The big takeaway here is that it's impossible for both players to reactively dodge.

Let's run through a few case studies and think about what it looks like from each player's point of view (I'm going to use 'Player A' as the aggressor/attacker, and 'Player B' as the defender, and it doesn't matter who has the higher ping between the players):

  • Player B is standing still in a room waiting and plans on starting to dodge the instant he sees Player A.  Player A turns the corner, gets a glimpse of Player B, and starts firing on him.  There is a significant delay before Player A sees Player B start to move, so Player A gets easy damage on a stationary target.  Player B, on the other hand, sees Player A turn the corner, starts dodging immediately, but finds that Player A gets a huge amount of damage on him no matter how well he dodges.
  • Player B is wildly spamming A/D/A/D in a room waiting.  Player A turns the corner, gets a glimpse of Player B, and starts firing on B.  Player A gets some shots off and it takes a while before Player B returns fire, but the erratic dodging prevents a fair bit of damage.  Player B's view has Player A turning the corner a little later than Player A saw it, and he'd take some extra damage in the fight compared to if both players were on LAN, however his preemptive dodging made a big difference.
  • Player B is low on health and hidden behind a pillar trying to live as long as he can to waste time, but Player A knows he's there.  Player B is spamming strafes in an attempt to prolong his life.  Player A picks one side of the pillar and just rushes it.  If Player B waits until he sees Player A, it's too late because Player A will get lots of shots off before Player B even tries to get back out of line of sight.  Player B could have tried his luck by randomly picking a time to run in one of the directions, but things could go very wrong for him no matter what he does.  This whole type of fight plays out completely differently on LAN, because Player B can reactively dodge and juke around the pillar while returning fire.

Final note: in games where fights last longer and you can see the hitscan beam that represents where players are aiming, there is a skill that can be developed related to reactively dodging your opponent's beam.  The unfortunate reality is that this skill only applies on LAN or at very low pings, and online you can't be sure enough about where your opponent is really aiming to know how you should be dodging.  This is a reason why some players are stronger on LAN and can cause highly skilled aimers to not be as effective on low pings.