While the ninth season of ESL’s Pro League came with many changes that greatly improved the competition’s prestige and integrity, the results of the first group stage so far clearly indicate that urgent lessons need to be learned about adapting round robin formats to CS:GO. While it works as a fairly reasonable option in sporting events like the World Cup of the Champions League, the specifics of Counter-Strike create way too many situations where second or third tiebreakers are required to separate the sides based on just three matches played.
Consider for a second how the last round of the European bracket’s Group B played out. After FaZe Clan’s win over NiP and subsequent qualification, all three other teams still had a chance to be eliminated, depending on the specific result of the match between Heroic and devils.one.
On the face of it, round robin competitions are the fairest of them all – everyone plays against everyone else, after all, making it more robust than a single-elimination or a GSL-style bracket. However, it only tends to work in small groups or massive leagues, with everything in-between leading to many meaningless games. In CS:GO, most round robin events were littered with such problems – most notably the BLAST Pro Series –, and while the Pro League’s group stage format is identical to other successful sporting events’ on the surface, we have seen way too many ties and corresponding odd tiebreakers here. Put simply, the margins are way too small after three matches of Counter-Strike – but why is that when the setup works so much better in football?
For starters, football is a low-scoring game, which has a dramatic impact on a system like this. Since draws are much more common (and not actually possible in the Pro League due to overtime), awarding only one point to each as opposed to the whole three for a win helps separate the sides. Worse yet, your “maps won” tiebreaker for a 2:0 win and an 0:2 loss in CS:GO is identical to a 2:1 and a 1:2 result, which will inevitably create more tiebreaker situations. Not only that, but goals scored or conceded is a much more tangible and reliable statistic as a tiebreaker. This is only in part because of their low count per match: the asymmetries of Counter-Strike also aren’t accounted for here. Rounds won is a useless tiebreaker metric if you played on Nuke while the other team played on Mirage, as a large edge in the first half will skew the stats. Similarly, if you only played two maps – either as a winner or a loser – rounds won and round score difference quickly become unreliable metrics as well when compared to teams that played three-map series.
In ESL Pro League Season 9, the tiebreakers go from map difference and map wins between the tied participants, then their overall map difference and map wins. The same goes for round score and round wins for the next four tiebreakers. It's a mess. Many DOTA 2 events use the Neustadtl score for their groups but they tend to feature more teams, making it a more useful metric.
There’s an easy solution to these issues, and it’s a minor tweak: instead of a best-of-three where the winner gets three points, play out all three maps no matter what, awarding one point for each map win. This rewards dominant wins and rewards you more for losing a close series – potentially creating ground to recover if you lose your home map but can make it happen on neutral grounds –, making it easier to separate the pack by creating extra data points to consider. It also eliminates the inherent asymmetry of round wins my using map wins instead as a tiebreaker and still won’t require the introduction of draws on 15-15.
While we can’t exactly compare the two systems with our current dataset, a quick examination shows that the hypothetical third maps played against FaZe would have provided a much more natural tiebreaking tool for the groups. It only makes sense: the ability to scrape out a map from the runaway winners should be rewarded, and you shouldn’t be denied the chance to score a point and play the third map others get to fight on just because you’ve lost the first two, at least not in a round robin format.
Don't think these systems are set in stone: the FACEIT Major's organizers famously decided to include the Buchholz tiebreaker system after reading about it on HLTV – adjustments like these are not that big of a challenge.