The 48 teams will be divided into 16 groups of three. The top two teams in each group will progress to a new knock-out phase of 32. It means that 16 teams will go home after playing just two matches, and critics have argued that a format featuring groups comprised of three teams is likely to be very unbalanced.
There is also, some say, a significant disadvantage to being the team that does not feature in the opening group game. Sixteen countries will start their campaigns against a team who have already played. If that team won their opening game they will know they only need a point to progress. If they lost it, they know they need a win to stand any chance of avoiding elimination. Both suggest a very different approach to a game where both teams start on zero points.
Supporters of expansion say the strength of the format is that while it adds 16 extra teams, it adds only 16 extra matches, and barely impacts the number of days it takes to play the tournament. The two teams who reach the final will have still played six matches to get there, as they currently do. In effect, 32 teams are still guaranteed to have at least three matches in the competition, which is what happens in the current 32 team format.