Starting 2027, the men's 50-over World Cup will feature 14 teams, 54 matches, and a return of the Super Sixes stage. It will be the first ODI World Cup since 2015 to feature more than ten teams, and the Super Sixes will be a throwback to the 1999 and 2003 editions. Here's a look at how the format of the World Cup has changed over the years.
Straight and simple - the early years (1975 to 1987)
Format: Two groups, top two from each progress to semi-finals, winners play the final
Length: 15 matches in 1975 and 1979, 27 matches in 1983 and 1987
The early years were uncomplicated, in terms of the format. The first four editions all featured eight teams, divided in two groups. In the first two editions, each team played the others in its group once, and then two from each qualified for the semi-finals, with the winners facing off in the final. That changed in 1983 (and stayed for 1987), but without any added complexities: the teams played each other twice in the group stages, that's all.
A common thread across the first three editions was that all the teams were usually in action on the same day, with some variations because of reserve days. The first three editions were completed in two weeks or just over, but the 1987 edition was stretched to a month, with the same number of matches as the 1983 edition but with more match days. It was also the first World Cup to be (a) held outside England, (b) played in two countries - India and Pakistan, and (c) have 50-over games, as opposed to 60.
The league experiment (1992, 2019)
Teams: 9 in 1992, 10 in 2019 (proposed for 2023)
Format: Each team plays the others, top four progress to semi-finals
Length: 39 matches in 1992, 48 matches in 2019
South Africa's readmission increased the number of teams to nine in 1992, and lengthened the tournament by eight matches. The group system was discarded and each team played the others once like in a league before the semi-finals. The 1992 edition began the normalisation of a World Cup lasting more than a month, as it has ever since.
The latest World Cup returned to this format, and the upcoming edition in 2023 is slated for the same before the new system comes into effect for 2027 and 2031.
The knockout years (1996, 2011, 2015)
Teams: 12 in 1996, 14 in 2011 and 2015
Format: Two groups, top four from each progress to quarter-finals
Length: 37 matches in 1996, 49 matches in 2011 and 2015
The 1996 World Cup involved the first major expansion and included 12 teams, as opposed to nine in 1992. More associate teams came into the fold as the teams were split in two groups, but the new format brought the tournament down from 39 to 37 matches.
The top four teams from the two groups qualified for the quarter-finals, with fixtures decided through a simple seeding system. Then semi-finals, and then the final.
The format came back in 2011 after criticism of the length in 2007, with the idea to shorten the tournament by a week or so.
The Super Sixes (1999, 2003)
Teams: 12 in 1999, 14 in 2003 (proposed for 2027 and 2031)
Format: Two groups, top three from each progress to Super Sixes (points from group stage carried forward), top four progress to semi-finals
Length: 42 matches in 1999, 54 in 2003
The format for the 2027 and 2031 World Cups will be sketched based on the Super Sixes that were previously used. The top three teams from the two groups go into a Super Sixes stage, where they play against the three teams from the other group. Points from those three games are added to the points carried forward from the group stages and the points table then gives you the semi-finalists.
The difference in the 1999 and 2003 editions was only in the calculation of the points carried forward. In 1999, only points against the other two qualifying teams from the group were carried forward. In 2003, points against non-qualifying teams were also considered, but with a lower weightage: one point for a win against a non-qualifying team and 0.5 for a tie or no-result, as opposed to four for a win and two for a tie or no-result against a qualifying team.
For instance, Zimbabwe qualified in 2003 and hadn't beaten Australia or India - the other qualifiers from their group. In 1999, they would have carried forward zero points, but they had 3.5 points going into the Super Sixes in 2003.
The Super Eights (2007)
Format: Four groups of four, top two from each progress to Super Eights (points against qualifying teams carried forward), top four from Super Eights progress to semi-finals
Length: 51 matches
The format itself was not well received. Four groups of four with the involvement of six associate teams meant some teams had more Test-playing nations in their groups than others. In theory, that increased the chance of upsets as the group stage was compressed to three games for a team. That is exactly how things played out, with Ireland and Bangladesh going through to the Super Eights at the expense of Pakistan and India, respectively.
The Super Eights stage then dragged on, and wasn't straightforward either. The top two teams from a group played six games in the Super Eights, as opposed to the normal seven in a round-robin format. Points for the seventh game were carried forward from the result against the other qualifying team from each group.
Varun Shetty is a sub-editor at ESPNcricinfo