The ICC T20 Championship is an international Twenty20 cricket competition run by the International Cricket Council. The competition is notional in that it is simply a ranking scheme overlaid on the regular T20I match schedule. After every T20I match, the two teams involved receive points based on a mathematical formula. The total of each team's points total is divided by the total number of matches to give a rating, and all teams are ranked on a table in order of rating. Australia currently leads the ICC T20I Championship, after the annual ranking update published on 1 May 2020.
Qualification
According to the ICC website, "teams will need to play six matches against other teams in the previous three to four years to remain in the rankings table."
Points calculations
Time period
Each team scores points based on the results of their matches over the last 3−4 years − all matches played in the 12–24 months since the May before last, plus all the matches played in the 24 months before that, for which the matches played and points earned both count half. Each May, the matches and points earned between 3 and 4 years ago are removed, and the matches and points earned between 1 and 2 years ago switch from 100% weighting to 50% weighting. For example, at May 2014, the matches played between May 2010 and May 2011 were removed, and the matches played between May 2012 and May 2013 switched to 50% weighting. This happens overnight, so can result in teams changing positions in the ranking table despite not playing.
Find the points earned from a match
Each time two teams play another match, the rankings table is updated as follows, based on the ratings of the teams immediately before they played. To determine the teams' new ratings after a particular match, first calculate the points earned from the match: If the gap between the ratings of the two teams before the match was less than 40 points, then:
Match result
Points earned
Win
Opponent's rating + 50
Tie
Opponent's rating
Lose
Opponent's rating − 50
If the gap between the ratings of the two teams before the match was at least 40 points, then:
Match result
Points earned
Stronger team wins
Own rating + 10
Weaker team loses
Own rating − 10
Stronger team ties
Own rating − 40
Weaker team ties
Own rating + 40
Stronger team loses
Own rating − 90
Weaker team wins
Own rating + 90
Example
Suppose Team A, with an initial rating of 100, plays Team B. The table shows the points awarded to the two teams for 9 different initial ratings for B, and the three possible match results. This illustrates that:
The winning team earns more points than the losing team.
Winning always earns a team100 points more than losing, and 50 more than tying.
The total points earned by the two teams is always the same as the total initial ratings of the two teams.
The points earned by a winning team increases as the initial rating of the opposition increases, within the constraints of earning at least its own initial rating + 10, and no more than its own initial rating + 90. A winning team therefore always earns more points than its initial rating, increasing its overall average rating.
The points earned by a losing team increases as the initial rating of the opposition increases, within the constraints of earning at least its own initial rating − 90, and no more than its own initial rating − 10. A losing team therefore always earns fewer points than its initial rating, decreasing its overall average rating.
In a tie, the weaker team usually earns more points than the stronger team, reflecting the fact that a tie is a better result for the weaker team than the stronger team. Also, the stronger team will earn fewer points than its initial rating, decreasing its average, and the weaker team more points that its initial rating, increasing its average.
For a given result, the rule of how the two teams' points are calculated changes as the initial ratings change, from being based on teams' own ratings when one team is far stronger, to being based on the opponent's ratings when the teams are closely matched, back to being based on own ratings when the other team is far stronger. However, despite these sudden changes in the rule, the number of points awarded for each result changes smoothly as the initial ratings change.
Find the new ratings
Each team's rating is equal to its total points scored divided by the total matches played..
Add the match points scored to the points already scored, add one to the number of matches played, and determine the new rating.
Points earned by teams depend on the opponent's ratings, therefore this system needed to assign base ratings to teams when it started.
Current rankings
Historical ICC T20I Champions
This table lists the teams that have historically held the highest rating since the T20I ranking was introduced. The summary of teams that have held the highest rating by days, are:
