[gwnn]

I often hear things like 'yea I was lucky' by many people in many sports. Of course in bridge it is a legitimate excuse, at least theoretically: say you bid an 80% grand slam and your opponents just bid 6 and you get to lose 15 imps. Even in chess, there is a certain 'fog of war' because you cannot calculate all variations to checkmate/overwhelming material advantage, so at some point you will need to rely on probabilistic means, i.e. "I think this Bxh7+ will lead to a 60% score and if I just build my attack more it will be 55%" - but neither thing is certain, even if you assume your opponent plays perfectly or you know how well your opponent will play.

What about some actual sports? I used to think that in football (either kind) it is not luck that you kick/throw the ball with a particular amazing accuracy, it is just skill+clutch effect. But of course even the most skilled players will have a certain statistical spread - maybe you need to kick the ball with a certain strength in a certain direction between 44 and 46 degrees to score* - the best player would maybe have 45+/-5 degrees (don't worry about this data please) if he hits it as accurately as he can: of course maybe I could only hit it at 40+/-20 degrees and only half the speed, so of course he deserves it when he scores but what if he doesn't score? Maybe the kick was good but he just was unlucky. I'm watching tennis now, of course the room for error in tennis is even smaller. One thing that I haven't really understood: if players apologise when they hit the top of the net and the ball passes, shouldn't the other guy apologise when the ball hits the top of the net and the ball comes back? Of course it's not their fault but still. What if one trained to hit the top of the net very frequently and thereby won a lot of points?

*part of the spread is related to a margin of error related to where the defenders/goalie is and part of the spread is related to lack of 100% accurate knowledge on air currents and so on.

[awm]

Often the difference is between intent and unforeseen circumstance. Like in tennis, if I win a point because I hit a good shot where I wanted it, that's viewed as skill (even though I might not actually be skillful enough to do it consistently, I did what I was trying to do). If I'm trying to hit a shot down the line and it bounces off the top of the net and into the middle of the court (but perhaps this wins me a point anyway because opponent was running toward the line to play the shot I intended to make) then this is viewed as luck -- I failed to make the shot I was trying for, but ended up scoring anyway. Of course if I was trying to hit the shot off the top of the net and actually did so, that would be viewed as skill, but in general tennis players do not try for that particular outcome.

Similarly in bridge, if I intentionally take a good line of play to make a contract that's skill. If a card drops out of my hand and the director requires me to play it, and it happens to be a brilliant play, that is luck. If I take a bad line of play that makes, the argument is that I failed in what I was trying to do (to select the best way of making the contract) but somehow received a good outcome (lucky) in any case.

[barmar]

The major luck factor in both physical and mental sports is that you generally can't predict what the opponent(s) will do, and sometimes you gain from errors on their part that you had little part in causing. Any time a tennis player wins a point because the opponent double faulted, that's almost totally luck on his part. It's not totally luck, though; for instance, having more stamina than the opponent is likely to result in him making more unforced errors than you late in the game (essentially, your skill is in outlasting the opponent).

[awm]

In general though, the apology is for making a mistake and profiting from it. If my opponent makes a mistake that causes me to score, that may be "luck" from my standpoint, but it's not something to apologize for (in fact that would be kind of rude). Similarly, if I'm high variance in some way (i.e. my tennis shot only rarely goes where I want it to go) I don't apologize when I am "lucky" and it works out (again, kind of rude). The apology is when I do something that was clearly a mistake (not at all what I was intending) and then it works.

[barmar]

I'm not familiar with the practice of apologizing to an opponent when one gains due to one's own error -- is this actually very common? In bridge, I apologize to partner when I do something stupid and we lose as a result.

And my response wasn't addressing the apology point at all, just the main question of luck vs. skill.

[nigel_k]

The outcome of many actions is randomly distributed - whether throwing a football or hitting a tennis ball or a golf ball. Being good just means your random distribtion has a smaller standard deviation. But whether or not you hit the target (receiver, inside of the court or fairway/green) is still going to be largely a result of luck.

[Phil]

Any type of event is made up of many small decisions / plays / opportunities. In a baseball game the difference between a great hitter and a mediocre one is one hit a week. Yet over a season the top teams will be .600 and the lousy ones .400. As opportunities increase so does the disparity of talent.

We tend to focus on the spectacular finishes of an event instead of what happened up to that point. In a tennis tie breaker where a ball that misses a line by 1" either way can determine a winner and that seems kind of random.

[Cyberyeti]

 barmar, on 2012-July-08, 13:39, said:

I'm not familiar with the practice of apologizing to an opponent when one gains due to one's own error -- is this actually very common? In bridge, I apologize to partner when I do something stupid and we lose as a result.

And my response wasn't addressing the apology point at all, just the main question of luck vs. skill.

I have apologised to opps in a couple of circumstances at the bridge table.

1. In a slam where the only point of the hand was Jx opposite Kxxx for 1 loser, the guy sitting over had the AQ but unfortunately discarded one a round before he should have done on the trump suit and had to play a low one when I led towards the K.

2. Where we had a completely messed up auction but ended up in a slam that required a long series of unlikely breaks and finesses and got them.

As to luck, think golf. Holing a chip where you played the shot perfectly and it was going to finish 6 inches away if it missed is fractionally lucky, but basically skill. Holing the same chip where you thinned it and the ball was going across the green and into the water if it hadn't hit the flag stick full on is luck.

The apology in tennis is because nobody tries to hit the top of the net, it just happens. You will also find they sometimes apologise when they play a perfect lob by accident when the ball hits the frame of the racquet and drops in when they were trying to drive the ball.

[Hanoi5]

Wouldn't you say that changing a player because of an injury and then having the replacement get injured is a bit of bad luck?

[gwnn]

 Hanoi5, on 2012-July-09, 06:53, said:

Wouldn't you say that changing a player because of an injury and then having the replacement get injured is a bit of bad luck?

Of course it is. Who would disagree? Of course good physical condition would reduce the probability of this scenario, but not to zero. So if it happens, your team is unlucky. Also if the referee makes a mistake, or if the weather changes... There are a lot of uncontrollable circumstances in most sports.

[barmar]

A hole in one in golf is luck -- skill gets you on the green, but is there anyone so accurate that they can put it into the cup on purpose?

There's also the butterfly effect -- a spectator can cough at an inopportune moment, or shift in their seat so that the sun reflects into a player's eyes, a ball can have a little extra wear, etc.

[TimG]

I think there are two different kinds of luck in sport.

There is the normal variation, the +/- 10% type stuff; whether you are firing on the +10% or -10% on any given day is a matter of luck.

Then there is the unplanned result, the net ball that trickles over, the grounder that takes a bad hop or hits a bag, the opponent that slips, the equipment malfunction, the gust of wind.

I think people are prone to apologize for the latter because they reduce the connection between skill and outcome.

[jjbrr]

Spoiler

[mgoetze]

 Hanoi5, on 2012-July-09, 06:53, said:

Wouldn't you say that changing a player because of an injury and then having the replacement get injured is a bit of bad luck?

If you were behind 0:2, and then subbed in a defensive midfielder for an offensive midfielder, and the new defensive midfielder got injured 5 minutes later, would you say that was bad luck or would you say it was a stupid idea in the first place?