Thursday, 21 November 2013
Tuesday, 12 November 2013
There’s no doubt the best sports stars are defined by their ability to consistently avoid defeat: Roger Federer at Wimbledon, Jose Mourinho at home and Floyd Mayweather in the ring. But are these sprees caused by great skill – or just good luck?
The characters listed above are all at the top of their respective professions, but why have they managed to put together winning runs above and beyond their – sometimes equally – talented peers, both past and present? The truth is that alongside their talent, luck is a key factor in establishing winning streaks.
Replacing characters with coins
If you step away from the performances and personalities of professional sports and think of these runs as mathematical occurrences, it’s much easier to understand how our perception of winning streaks is skewed. Take the ‘Pretty Boy’ for now, and imagine matches as coin tosses rather than skill-based competitions.
If you were to toss a coin 100 times, probability dictates that you’ll have a 75% chance of seeing a streak of at least 6 heads (or tails) occurring in a row, and a 10% probability of witnessing a streak of at least 10 consecutive heads (or tails).
Imagine if that sequence were shown to you in the following fashion, with “O” representing heads and “X” representing tails:
As a human, you’re naturally drawn towards the easiest definable pattern – the big sequence of Os in the fourth row. Does that mean this period is more notable than the others? Did heads take the initiative? Did it show great skill? No – it is a coin. Probability dictates that sometimes these sequences just happen.
For tennis players, boxers, managers etc., any run of form – although winning streaks are particularly poignant – can skew our judgment in a similar manner to the pattern above, and also cause us to overestimate the chances of the pattern continuing.
For example, having replaced O’s and X’s with W’s and L’s (for wins and losses), look at the following pattern:
On your first impression, what result do you believe fills in the “???”? Most people would imagine that the winning would continue. Now take a look at this image:
What do you imagine fills in the ??? here? Naturally, we continue the pattern and enter “WWWWW” – even though anything could fill this space. Why? Purely because the human brain naturally creates patterns and sticks to them – even if there’s no rationale behind it.
The skill factor
Of course, no one would suggest that the greatest sports personalities achieved their feats through randomness alone. It’s obvious that their talent has allowed them to be in a position to achieve such feats. In essence, their skill makes them a weighted coin, more disposed to landing on “H” (or win) than some others, but it’s by no means a definite outcome.
For example, when Rafael Nadal plays on a clay court he could be considered a very heavily weighted coin. His clay-court win percentages over the last five tennis seasons were 96%, 93%, 100%, 92%, 96%. With an average of 95.4%, it’s obvious Nadal’s wins aren’t caused by luck, but chance could have played a big part in his perfect season in 2010.
So is the reason Federer dominated at Wimbledon because he was much better than Pete Sampras? Or are the Heat as good as the 1970s Lakers side after their recent streak?
The answer is maybe. Realistically, winning streaks are due to a combination of factors – one of which is luck. By ignoring the input that chance has, we leave ourselves victim to over-rating the chances of teams on winning streaks.
In American sports, chance could be considered as playing a bigger part in proceedings, as the egalitarian structure ensures that there is a fairer division of talent between teams, and therefore less opportunity for a single team to dominate as in European soccer.
Aside from winning streaks, the same caution should be applied to using any form guides as an indicator. Should we really believe that a team with a five-game form of LLWWW will beat a team at WWLLL?
Tuesday, 5 November 2013
Whether a golfer, soccer player or tennis star, professional sportsmen hate to lose. That’s obvious. But did you know that athletes actually perform better in situations where they are striving to avoid defeat, rather than if they were just aiming to win?
The psychology behind this “loss aversion” is simple: humans hate to have things taken away from them. As such, if an outcome is framed as “losing”, sportsmen and women will perform extra-hard to avoid it. There’s been a lot of research on the subject, but one the most potent real-world examples is on the PGA Tour, which demonstrates the effect of loss aversion on professional golfers.
After studying 2,525,161 putts from the PGA Tour between 2004 and 2009, researchers Devin Pope and Maurice Schweitzer observed that a disproportionate number of putts for par were completed compared with attempts for a birdie. A huge 82.9% of putts for par were successfully completed, while just 28.3% birdie attempts were sunk.
Of course, not all putts are equal, and it’s likely that many of the birdie attempts were from more difficult distances than the par attempts. However, even when the researchers averaged-out the distances, golfers still putted 3.7% more shots for par than for birdies. But why?
The researchers theorised that loss aversion must pay a part. While both situations – missing a birdie and missing a par putt – mean that the player is one shot worse-off, psychologically, sinking a birdie will always be considered as “winning” a point – putting the golfer one-under. A bogey will always be seen as losing a point (one-over), and therefore the golfers seem to up their game for losing situations.
Loss aversion also leads to another golf-specific issue. Player’s birdie putts – when missed – tend to go short, putting them in a more advantageous position should they miss the hole. Over-hitting risks putting the player in a position that could be even worse.
Loss aversion for other sports
Loss aversion is easily quantifiable in golf, but it’s also a phenomenon that can have a big impact on a variety of sports and situations. An obvious example is towards the end of soccer matches.
If a team is winning, they tend to become more defensive towards the end of a game, rather than try to attack to extend their lead. This happens despite the fact that league structures reward teams who score more (goal differences) or in two-legged ties where aggregate scores can prove vital.
To some extent, it also goes in the face of common sense – teams who have been performing well alter their tactics, despite their original strategy giving them the advantage to begin with.
The change in tactic can be attributed to human heuristic called endowment theory. Endowment theory states that a person – or in this case, a team – becomes even more loss averse when they have already gained something. Therefore because teams start games at 0-0, when they score a goal (or are endowed with it), they reframe the match in the new terms.
Considering their 1-0 advantage, the team’s desire to score more goals lessens, because a win and two goals is only marginally more valuable than a win and one goal, but both are worth more than a draw,
Loss aversion could also explain the tactics employed in the first leg of a two-legged tie. Away teams tend to approach the game defensively, opting to counter-attack, while home teams strive to avoid conceding an “away goal”, which is valued at more than a home one.
Reference points, not three points
The avoidance of conceding in a two-legged cup-tie is a good example of how it’s not just for the end result that can be influenced by loss aversion, but also the desired outcome.
If a team expects to win a game 3-0, the side could be loss averse to anything but that final outcome. This is because that score is a “reference point” – the outcome the team expects to achieve. Anything less than that outcome would be a disappointment. Likewise, if a home team in a cup-tie wants to avoid conceding, loss aversion wouldn’t just apply to the match outcome but also to conceding a goal.
An example of loss aversion for tennis
One of the biggest examples of loss aversion occurs in tennis, usually twice per service game. Tennis stars across the spectrum (and almost without exception) utilise a slower second serve to avoid committing a double fault and automatically losing the point.
However, while only 65% of first serves go in, 75% of those points go in favour of the server. For second serves, the result is 50/50. That means the potential win percentage for a fast first serve and a slow second serve is 66.3%. If two fast serves are used, it’s 75%.
This loss aversion in tennis serves actually costs players an 8.7% chance of winning the service point.
Loss Aversion and Bettors
Loss aversion isn’t limited to professional golfers and soccer teams. Bettors can also suffer the influence and make irrational decisions because of it. We’ll be discussing that in more detail in the coming weeks.