Most common way to rank players or teams in round-robin tournament
Round-robin tournament is widely applied in competitions which are able to be held for a long period and need a comprehensive ranking of the players or teams. In order to acquire the ordering of teams and player, the most convenient and common way is to rank the participants according to their total victories. Nevertheless, tie may appear in an individual competition of the whole tournament.
Considering three possible outcomes of a match, different scores are rewarded for having a winning, tie and losing game. The method used in the well-known English professional football league, Premier League, can be taken as an example here. Premier League is constructed by the competitions between the 20 top football clubs in England, in which double round-robin tournament is used, implying each team competes with all other teams twice. Three, one and zero point will be rewarded for a win, tie and lose in each competition. In the end of the league, a ranking list will be mainly arranged by the total scores of each team.
Problems arisen by ranking with total scores
Yet, this method may not be a perfect one when taking account of the outcome and fairness. Firstly, the total scores of the top two teams may be the same, showing that comparing only score is possibly inadequate to decide the champion. Secondly, the ranked ordering does not accurately reflect each team’s ability as a victory against a stronger team is more worthy than a win against a weaker team. (M. Stob,1985)
Solution to the problem of tie in ranking
To tackle the first problem, other criteria can be added into the arrangement of ranking by considering the nature of that sport itself. Referring to figure 1, the top two clubs have the same points but different ranking in