Analysis: researchers have crunched 53 years of data from 47,710 matches to find out the answer.

"On his day Ronnie O'Sullivan is unplayable", "Steve Davis' record in the World Championship speaks for itself", "Hendry was a winning machine, he just didn’t miss". If you’ve ever found yourself in the company of two people debating who owns the title of snooker’s all-time greatest player, you’ve heard phrases just like the above (with their favourite player appropriately substituted).

Of course, you may be naïve to the intricacies of this great debate, but there is no doubt an equivalent argument in which you’ve taken part: Pelé or Maradona? The Rolling Stones or The Beatles? Kendall or Kylie? Whatever your area of interest, humans have an intrinsic desire to rank things. Just think about the Oscars, the GAA All Stars, Time Person of the Year....the lists go on and on.

However, these arguments tend to be a never-ending rabbit hole which ultimately concludes with two people agreeing to disagree. The main problem is that rankings tend to be based upon personal preference with an extremely high level of subjectivity (the player who scored the goal that won their team the cup, the movie they saw on their first date etc). In an ideal world, any ranking would be made using an entirely objective approach which, unfortunately, requires detailed data describing the interactions between different entities to determine who exactly is the best.

We need your consent to load this YouTube contentWe use YouTube to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

From Eurosport snooker vodcast The Break, who's the greatest player of all time?

While this can prove difficult in most domains, one area in which there is no shortage of detailed historical data of competition is within the field of sport. Motivated by this, researchers at MACSI in the University of Limerick have published a scientific article in which the exact question that began this article is considered: who is the greatest snooker player of all time?

To answer the question in a quantitative manner, the first thing needed was detailed data of results from the sport. This was obtained via a large data scraping exercise (involving pulling statistics from multiple webpages) resulting in a collection of match results from over 50 years (1968-2020) amounting to 657 tournaments featuring 1,221 unique players competing in 47,710 matches.

With this data to hand, the question is then how best to use it in ranking the competitors. Perhaps the most obvious thing to do would be to simply count the number of times each player had won. This would be the equivalent of giving the Oscar to the highest grossing movie so it's not ideal. The issue with this approach is in the fact that the player with the most wins could simply repeatedly play Joe Bloggs at the snooker hall.

Snooker's complex network. The top 50 players based upon our prestige ranking where the size of the circles represent their associated prestige while the weight of the lines joining two players indicate the number of times that one player has lost to another.

In order to offer an alternative approach, we make use of the network description of this data. In particular, we consider not only how many times one player defeated another but also how frequently the defeated player themselves defeated others. In this sense, each player has some associated prestige describing their quality and in defeating a player the winner receives some of this associated prestige. This implies that a win against a strong competitor with high prestige is now more worthwhile to a player’s rank than defeating a weaker competitor.

This calculation may seem extremely involved, but is readily doable in seconds with modern computers. Using all matches played alongside their results, we can quickly determine who the greatest player of all time is according to the proposed approach. Interestingly, it isn’t O’Sullivan with his natural talent, Davis and his distinguished trophy room or the winning machine known as Hendry, but rather the four-time world champion John Higgins.

Comparison between Top 30 players ranked by prestige and number of wins. Generally, there is a very strong agreement between the two, but useful information regarding the quality of a player's wins is available

This result may seem surprising to some but when the data is actually considered it is entirely understandable. While both Davis and Hendry have plenty of trophies and wins to their name, the quality of player competing in their era was considerably less than those faced by Higgins and O'Sullivan (who is ranked the second greatest through our approach).

For those with an interest in snooker this is readily observed above where we show the top 30 players ranked using our prestige approach compared to their number of wins. While the two ranking schemes are clearly very correlated, we can obtain a considerable amount of information from this figure. In particular, those players who are above the red line (Davis, Hendry, Jimmy White etc) have obtained their wins from less competitive games. The alternative is true for those below the line, many of whom are from the modern era.

Snooker's greatest of all time (per the data): John Higgins

To offer a remedy for the intrinsic human desire to rank things, we have utilised a mathematical framework that can help in determining a ranking of competitors which considers, not only the number of times a player has won but also the quality associated with each win. This concept offers plenty of room for extension to any domain with detailed data on interactions (unfortunately it may prove tricky in the case of the Kardashians) and can help in ending the many arguments about the greatest competitor in your favourite area of interest.

Further details on this work and extended analysis can be found here. This research was funded by Science Foundation Ireland (16/IA/4470).

The views expressed here are those of the author and do not represent or reflect the views of RTÉ