Rob Minto

Sport, data, ideas

Month: January 2015

Nadal, Berdych and the upper limit of winning streaks

462326540Tomas Berdych must be a relieved man. Having lost 17 times in a row to Rafael Nadal, he has finally snapped the streak at the Australian Open.

Had he lost, it would have been a new record. Tennis rivalries do often produce one-sided periods, but 17 wins for one player in a row is the upper limit. It’s the number of consecutive wins that Bjorn Borg had over Vitas Gerulaitis; that Ivan Lendl had over Tim Mayotte; and Lendl had over, surprisingly, Jimmy Connors.

Weirdly, the upper teens seems to be the limit in other sports streaks too: the Australian cricket team went on a 16-test winning streak in 1999 to 2001. Both New Zealand (twice) and South Africa hold the record of 17 straight test wins in rugby. And Spain’s football team had a 15-game winning run.

Is there a mathematical reason for 15 to 18 being the upper limit of streaks? If it were a coin toss, then probably yes. But sport isn’t a coin toss. The win streaks get harder as teams put pressure on themselves to perform, and opponents look to topple the team of the moment. Of course, it’s easy to give a bad performance, and teams get injuries, or retirements.

The tennis streaks mentioned above have ended at 17 as one of the players retired. The interesting thing about Berdych’s victory is that it is the first reversal. Nadal may have been under par, but the pressure would have been on Berdych to win, rather than in team sports where the pressure piles onto the streak holder.

So which is the next longest active head-to-head winning (or losing) streak? I can’t find a definitive list, but I wouldn’t be surprised if it’s Richard Gasquet against, you guessed it, Nadal. The scoreline is 0-13 in Nadal’s favour.

That quote

As Gerulaitis said after he beat Connors in 1980: “nobody beats Vitas Gerulaitis 17 times”. Except the ATP record shows that his losing streak against Connors was 12, and was 16 against Borg. (There is a walkover for Gerulaitis in 1978, which you might think counts as a win, but the ATP seems to not count them in the head to heads.) I have no idea where the missing 17th match is.

When it comes to FA Cup upsets, size is subjective

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Bradford: biggest shock EVER?

What’s the biggest FA Cup shock defeat ever? For Robbie Fowler, it’s the Chelsea 4-2 loss to Bradford from yesterday (Jan 24). And in terms of drama, it’s clearly a great story. After all, Chelsea were 2-0 up and at home.

But for league placings, it’s not even close. With Chelsea top of the premiership, and Bradford 7th in League 1 (the third tier, despite its name), there are 39 teams between them.

Compare that to the 84 teams between Blackburn and Oxford in 1964, which according to Steve Porter, author of The Giant Killers website is the greatest FA Cup upset ever. Blackburn were 2nd at the time in the top division; Oxford were 18th in league 4.

Porter, who writes under the name Captain Beecher, ranks the upsets in terms of league placings, combined with a player quality metric using internationals and previous cup winners. Porter doesn’t spell out his methodology, but it’s clearly better than just using collective memory and non-scientific lists published in newspapers.

Porter sums up the problem perfectly:

On BBC’s Match of the Day programme, when asking the public if Bradford’s victory over Chelsea was the greatest cupset ever, they showed twelve of what they considered the greatest giant killings of all time. Every game had one thing in common. The BBC TV cameras were there. Not one game which was not covered by the BBC was considered. And so shapes our opinion. If you’re told something was a huge giant killing enough times {7th placed top flight Wimbledon beating Champions, Liverpool 1-0 in 1988. Surprise? yes but giant killing? Really? 7th vs 1st in the Premier League?} You start to accept that it’s true. ITV are a little more impartial, perhaps because they don’t have as much cup footage to be able to make lists exclusively thiers. The problem when compiling such lists is that every time a particular tie is overlooked, it’s chances of being placed in the next TV countdown, or magazine article diminishes.

And where does Porter’s system put Chelsea-Bradford? It’s 15th on his all-time list. Not bad, but it is interesting that it is lower down than non-league Luton’s 1-0 victory over the Premiership’s Norwich only 2 seasons ago, which is in 7th place. That didn’t even make the BBC’s list in the studio analysis. Memories are short, eh?

Being subjective, turning round a 2-goal deficit to 4-2 at Stamford Bridge is an extraordinary result. But perhaps the BBC could, with all its resources, dig up a few proper stats like Porter’s.

See also:
Interactive football league tables

Should Roger Federer keep going?

461996002Roger Federer’s third round loss at the Australian Open will raise the usual questions about this late stage of his career. Should he call it quits now? Has his time passed?

It seems odd to be urging the world’s second best player (by ranking) to retire. The heart says keep on going. The head?

There have been only 11 men in the open era of tennis to win a major in their 30s. Only four (Laver, Rosewall, Connors and Agassi) have done it more than once. For Federer to join that band, he will have to defy not just age, but statistics.

As players enter the later stages of their career, the big wins dry up. So far, the biggest gap in terms of days from penultimate major to last is Arthur Ashe, who took nearly 2,000 days between his 1970 Australian Open and 1975 Wimbledon victory.

Ashe’s gap is something of an oddity. If we look past, Federer is next with nearly 900 days between his 2010 Australian Open and 2012 Wimbledon win. That’s ahead of Sampras (791 days) from Wimbledon 2000 to the US Open 2002. Even Agassi took over 700 days between his final two slam wins in Australia.

For Federer to win another, the gap would be at least 1,000 days by the time we get to the French or Wimbledon in the summer of 2015. Not impossible, but unlikely.

In terms of slams, Federer’s last gap of 10 events is already higher than the gaps Agassi (8) and Sampras (9) posted between penultimate and last wins. If Federer were to win a slam in 2015, it would be 11, 12 or 13 slam events since his last victory – a gap that looks less and less likely to be bridged.

In other words, recent history shows that it just won’t happen. Last hurrahs don’t happen twice – and Federer has already had his.

Gap in days between penultimate and last major titles
(men over 30 in open era)

Ashe 1985
Federer* 889
Sampras 791
Agassi 728
Newcombe 479
Connors 364
Rosewall 354
Laver 65

* For Federer to win another slam, at least 1,064 days will have elapsed.

The economics of kids’ birthday parties

Fantastic story out today (Mon, Jan 19) about a parent being invoiced for a kids’ party no-show. You can read the Guardian’s take here, and the BBC here.

The obvious reaction is to dismiss the invoice sender as a complete nutcase, and the no-show parents as arses for going to the press.

But pick it apart for a moment, and there’s a fundamental misunderstanding. Continue reading

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