Rahul Sharma (Editor)

ICC T20I Championship

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Format
  
Twenty20 International

Last tournament
  
ongoing

First tournament
  
2007

Number of teams
  
17


Administrator
  
International Cricket Council

Tournament format
  
notional (ongoing points accumulation through all matches played)

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.

Contents

Currently, New Zealand leads the ICC T20I Championship.

Qualification

According to the ICC website, "Only teams who have completed at least eight T20 international matches since 1st August between three and four years ago will have their rating above converted into a ranking on the main table."

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 (the matches from May 2011 to April 2012 would have already been at 50% following the previous rerating). 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:

If the gap between the ratings of the two teams before the match was at least 40 points, then:

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 (ranging from 20 to 160), and the three possible match results.

This illustrates that:

  • The winning team earns more points than the losing team. (Unless the ratings are more than 180 apart and the weaker team wins − highly unlikely.)
  • Winning always earns a team 100 points more than losing, and 50 more than tieing.
  • 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 (quality) 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 (quality) 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 (unless the initial ratings are at least 80 apart), 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. (Series are not significant in these calculations).
  • Add the match points scored to the points already scored (in previous matches as reflected by the table), 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.

    • Historical ICC T20I Champions

    This table lists the teams that have successively held the highest rating since the T20I ranking was introduced.

    References

    ICC T20I Championship Wikipedia
    (Text) CC BY-SA