Are winning streaks caused by great skill or good luck?

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.

Click here to read how a second piece of the human psyche, The Gambler’s Fallacy, also plays a part in our decision.

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?