It seems that, according to most accounts, the new All-Ireland format is very popular. A massive increase in the number of competitive matches, meaningful draws, and the addition of home matches for (nearly) every team have all been positive outcomes of this round robin structure. However, while it seems to be an improvement over the old system, the new format is not without its flaws.

There is imbalance between Leinster and Munster, as relegation to the Joe McDonagh tier only looms for Munster teams if Kerry suddenly become a dominant hurling power. While Kerry are safe from relegation this year, and they managed to win a pre-season game against Cork last winter (Kerry’s first win over them since their All-Ireland win in 1891) they are also at zero risk of reaching the 2018 Joe McDonagh final, so this seems unlikely for the time being.

Another issue is the imbalance with the home venues; Walsh Park in Waterford was deemed unfit for championship matches, and so Waterford have been forced to play their ‘home’ games at neutral grounds. Additionally, due to unusual rules from the GAA, these neutral grounds must be in Munster; instead of having a quick drive up to Nowlan Park for their match against Tipperary, they instead had to play in the Gaelic Grounds; this stadium is only about 20 minutes from the Tipperary border, whereas you have to tack on at least an extra hour to reach county Waterford.

The main issue, however, has been the imbalance in the frequency of matches. All teams in Leinster and Munster must play 4 matches in 5 weeks. However, there are four teams that must play these in consecutive weekends, with no gap in between, and another four who will have 3 matches in a row. This can be a big disadvantage, in an already tough schedule, as teams don’t have the same amount of time to recover and prepare. The question is, however: how large is this disadvantage, and what can be done about it?

Wins over expectation

It’s already been pointed out that, at time of writing, no team has won a match in their third or fourth week in a row; the current record is four losses and two draws. However, it’s important to consider that the losing team was not the favourite coming into this fixture; It seems likely that Offaly would still have lost to Wexford or Dublin in week one, for example. As such, it’s important to look at the expected result of the match.

In order to get an expected result, the BAINISTEOIR ratings for each team at the time of the match were used. These ratings are not perfect, but overall tends to perform well; its favourite has gone on to win over 70% of this year’s matches in divisions 1A and 1B of the league, and the Leinster, Munster and Joe McDonagh groups in the championship, at time of writing. Though the BAINISTEOIR rating system does account for time between matches, it doesn’t calculate this as an advantage for either team; it simply reduces its certainty when the teams haven’t played in a while.

All matches in Leinster and Munster where there were a difference between how many consecutive weeks each team had played were looked at. So far, there have been 8 such matches. It is worth noting that this is a small sample size, so any results below could still change.

For each match, their actual result minus their expected result was plotted against the difference in consecutive weeks played. For example, when Wexford beat Dublin, they were given a 76% chance to win, so their ‘actual minus expected’ value equals 0.24. Dublin were given a 19% chance to win (the remaining percentage is the chance of a draw), so their ‘actual minus expected’ was -0.19. This was Dublin’s second week in a row, and Wexford’s first, so Dublin had a ‘consecutive week difference’ of 1, while Wexford’s was -1. The graph below displays the results for all 8 games: