{"id":3100,"date":"2018-10-18T13:59:43","date_gmt":"2018-10-18T13:59:43","guid":{"rendered":"http:\/\/www.tennisabstract.com\/blog\/?p=3100"},"modified":"2018-10-18T13:59:43","modified_gmt":"2018-10-18T13:59:43","slug":"daniil-medvedevs-leading-elo-indicator","status":"publish","type":"post","link":"https:\/\/www.tennisabstract.com\/blog\/2018\/10\/18\/daniil-medvedevs-leading-elo-indicator\/","title":{"rendered":"Daniil Medvedev’s Leading Elo Indicator"},"content":{"rendered":"

Italian translation at settesei.it<\/em><\/a><\/p>\n

It is shaping up to be a breakthrough season for 22-year-old Russian Daniil Medvedev<\/a>. His Tokyo title two weeks ago was his first at the ATP 500 level and his third on the season, after earlier triumphs in Sydney and Winston-Salem. The run in Japan was a particularly notable step, since he knocked out three top-20 players along the way. He had only four top-20 victories in the entire season leading up to Tokyo, and two of those were against the slumping Jack Sock<\/a>.<\/p>\n

His ATP ranking is rising alongside his results. The Winston-Salem title moved him into the top 40, and the Tokyo trophy resulted in a leap to No. 22. After a first-round win in Shanghai last week, Medvedev crept to his current career-high of No. 21. With a couple of wins in Moscow this week, he could overtake Milos Raonic<\/a> and reach the top 20.<\/p>\n

The improvement on the ATP ranking table is nothing next to the Russian’s race to the top of the Elo list. Last Monday, with the Japanese title in the books, Medevdev rose to No. 8 on my men’s Elo ranking<\/a>. Since then, he has dropped two places but remains in the top ten, ahead of Marin Cilic<\/a>, Kevin Anderson<\/a>, and a host of others who outrank him on the official ATP list.<\/p>\n

Given the discrepancy, what do we believe? Is Medvedev inside the top 10 or outside the top 20? Is Elo a leading indicator–that is to say, an early-warning signal for future ATP ranking milestones–or a misleading one? Elo is designed to be forward-looking, tuned to forecast upcoming match outcomes and weighting wins and losses based on the quality of the opponent. The official rankings explicitly consider a year’s worth of results, with no adjustments for quality of competition. In theory, Elo should be the better of the two measures for predicting longer-term results, but that assumes the algorithm works well, and that it doesn’t overreact to short-term successes. Let’s take a look at past differences between the two systems and see what the future might hold for the 22-year-old.<\/p>\n

Precedents<\/strong><\/p>\n

Since 1988, 102 men have debuted in the ATP top ten. A slightly larger number, 113, have shown up in the top ten of my Elo ratings. There’s a very substantial overlap between the two, with 94 names appearing in both categories. Thus, 8 players have reached the ATP top ten without clearing the Elo threshold, while 19 have rated a spot in the Elo top ten without convincing the ATP computer to agree.<\/p>\n

Here are the eight ATP top-tenners whose Elos have never merited the same status:<\/p>\n

Player               ATP Top Ten Debut  ATP Top Ten Weeks  \nJonas Svensson                19910325                  5  \nNicolas Massu                 20040913                  2  \nRadek Stepanek                20060710                 12  \nJurgen Melzer                 20110131                 14  \nJuan Monaco                   20120723                  8  \nKevin Anderson                20151012                 31  \nPablo Carreno Busta           20170911                 17  \nLucas Pouille                 20180319                  1<\/pre>\n
A few of these players could still make progress on the Elo list, especially Kevin Anderson, who is currently 11th, a miniscule five points behind Medvedev.<\/p>\n
Here is the longer list of Elo top-ten players without any weeks in the official top ten:<\/p>\n
Player                 Elo Top Ten Debut  Elo Top Ten Weeks  \nCarl Uwe Steeb                1989\/05\/22                  3  \nAndrei Cherkasov              1990\/12\/11                  1  \nGoran Prpic                   1991\/05\/20                  1  \nDavid Wheaton                 1991\/07\/08                  9  \nJerome Golmard                1999\/05\/03                  2  \nDominik Hrbaty                2001\/01\/15                  2  \nJan Michael Gambill           2001\/04\/06                  6  \nNicolas Escude                2002\/02\/25                  4  \nYounes El Aynaoui             2002\/05\/20                  2  \nPaul Henri Mathieu            2002\/10\/14                  8  \n\nPlayer                 Elo Top Ten Debut  Elo Top Ten Weeks\nAgustin Calleri               2003\/05\/19                  2  \nTaylor Dent                   2003\/10\/06                 10  \nAndrei Pavel                  2004\/05\/10                  2  \nRobby Ginepri                 2005\/10\/24                  1  \nIvo Karlovic                  2007\/11\/12                  3  \nRoberto Bautista Agut         2016\/02\/22                  1  \nNick Kyrgios                  2016\/03\/04                 62  \nStefanos Tsitsipas            2018\/08\/13                  3  \nDaniil Medvedev               2018\/10\/08                  2<\/pre>\n
* I define ‘weeks’ a little differently for Elo ratings, as ratings are generated only for those weeks with an ATP-level tournament or Davis Cup tie.<\/em><\/p>\n
Most of these guys came very close to cracking the ATP top ten. For example, David Wheaton<\/a>\u2019s peak ranking was No. 12. With the exception of Nick Kyrgios<\/a>, no one spent more than ten weeks in the Elo top ten without eventually reaching the same standard according to the ATP formula. This list shows that it’s possible to have a brief peak that cracks the Elo top ten but doesn’t last long enough to reflect the kind of success that the official ranking system was designed to reward. About one in six players with a top-ten Elo rating never reached the ATP top ten, though as we can see, the odds of remaining an Elo-only star fall quickly with each additional week in the top ten.<\/p>\n
Kyrgios is a perfect example of the differences between the two approaches to player ranking. The Australian has recorded a number of high-profile upsets, which are the fastest way to climb the Elo list. But knocking out the second-ranked player in the world, as Kyrgios did to Novak Djokovic<\/a> at Indian Wells last year, doesn’t have much impact on the ATP ranking when it happens in the fourth round. Usually, a player who can oust the elites will start piling up wins in a form that the official computer will appreciate. But Kyrgios, unlike just about every player in history with his talent, hasn’t done that.<\/p>\n
In short, Elo will always elevate a few players to top-ten status even if they’ll never deserve the same treatment from the ATP formula. It’s too early to say whether Medvedev fits that mold. But where Elo really excels is identifying top players\u00a0before<\/em> the ATP computer does. Of the 94 cases since 1988 in which a man debuted in both top tens, Elo was first to anoint the player a top-tenner in 76 of them–better than 80%. The official rankings were first 10 times, and the two systems tied in the other eight instances. On average, players reached the Elo top ten about 32 weeks before the ATP top ten.<\/p>\n
Here are the 11 most extreme gaps in which Elo got there first, along with the top-ten debuts of the Big Four:<\/p>\n
Player               ATP Debut   Elo Debut  Week Diff  \nMariano Puerta      2005\/07\/25  2000\/06\/12        267  \nMarc Rosset         1995\/07\/10  1990\/11\/05        244  \nFernando Gonzalez   2006\/04\/24  2002\/10\/07        185  \nGuillermo Canas     2005\/05\/09  2002\/08\/05        144  \nMikhail Youzhny     2007\/08\/13  2004\/11\/15        143  \nGaston Gaudio       2004\/06\/07  2002\/04\/29        110  \nRichard Gasquet     2007\/07\/09  2005\/06\/20        107  \nTomas Berdych       2006\/10\/23  2004\/10\/11        106  \nRobin Soderling     2009\/10\/19  2007\/10\/08        106  \nMark Philippoussis  1999\/03\/29  1997\/03\/24        105  \nJack Sock           2017\/11\/06  2016\/01\/18         94  \n                                                       \nPlayer               ATP Debut   Elo Debut  Week Diff  \nRoger Federer       2002\/05\/20  2001\/02\/19         65  \nAndy Murray         2007\/04\/16  2006\/08\/21         34  \nNovak Djokovic      2007\/03\/19  2006\/07\/31         33  \nRafael Nadal        2005\/04\/25  2005\/02\/21          9<\/pre>\n
And in case you’re curious, the ten cases in which the ATP computer beat Elo to the punch:<\/p>\n
Player              ATP Debut   Elo Debut  Week Diff  \nStan Wawrinka      2008\/05\/12  2010\/10\/25        128  \nDavid Ferrer       2006\/01\/30  2007\/05\/28         69  \nJanko Tipsarevic   2011\/11\/14  2012\/05\/13         26  \nRainer Schuettler  2003\/06\/09  2003\/08\/25         11  \nTommy Robredo      2006\/05\/08  2006\/07\/24         11  \nFernando Verdasco  2009\/02\/02  2009\/04\/06          9  \nAlbert Costa       1997\/04\/21  1997\/05\/26          5  \nNicolas Almagro    2011\/04\/25  2011\/05\/22          4  \nJohn Isner         2012\/03\/19  2012\/04\/15          4  \nJiri Novak         2002\/10\/14  2002\/10\/21          1<\/pre>\n
The 32-week average difference is suggestive. As I’ve noted, Elo ratings are optimized to forecast the near future, so at least in theory, they reflect each player’s level\u00a0right now<\/em>. The ATP algorithm tallies each man’s performance over 52 weeks, with equal weight given to the first and last weeks in that timeframe. Setting aside improvement and decline due to age, that means the ATP computer is telling us how each player was performing, on average, 26 weeks ago. If Medvedev continues to oust top-20 players on a regular basis and claims another 500-level title or two, he could well be 26 or 32 weeks away from a top-ten debut.<\/p>\n
Elo isn’t designed to make long-term forecasts–the tools needed to do so, for the most part, have yet to be invented. And the system occasionally gives high ratings to players who don’t sustain them for very long. But in general, a superlative Elo rating is a sign that a similar mark on the ATP ranking list isn’t far behind. So far, Kyrgios has managed to defy the odds, but the smart money still points to an eventual ATP top-ten debut for Medvedev.<\/p>\n","protected":false},"excerpt":{"rendered":"
Italian translation at settesei.it It is shaping up to be a breakthrough season for 22-year-old Russian Daniil Medvedev. His Tokyo title two weeks ago was his first at the ATP 500 level and his third on the season, after earlier triumphs in Sydney and Winston-Salem. The run in Japan was a particularly notable step, since … Continue reading Daniil Medvedev’s Leading Elo Indicator<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[32,40],"tags":[],"class_list":["post-3100","post","type-post","status-publish","format-standard","hentry","category-elo-ratings","category-forecasting"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/posts\/3100","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/comments?post=3100"}],"version-history":[{"count":0,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/posts\/3100\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/media?parent=3100"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/categories?post=3100"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/tags?post=3100"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}