The Ratings Ladder Explained

By Greg Schmidt - TUC Webmaster

There have been many changes to the TUC web site in the two years I've been volunteering as webmaster. Some of these changes are very visible, some less so; some are easily understood, some are less clear. I'm going to do my best to shed some light on one change that has generated a lot of questions: the ratings ladder scheduling system.

History

Many of us have experienced problems with tiered leagues. These problems include:

• teams being "trapped" in a tier where the level of play is too high or too low for them, resulting in a series of lopsided games
• delays caused by trying to schedule five weeks of games at once
• inflexibility in rescheduling games, since results must be in by the end of the round

The ratings ladder is the latest incarnation developed by the original Leaguerunner writers at OCUA in response to these and other problems. TUC first experimented with the ladder in the Monday Premier Co-Ed Indoor league in the winter of 2007. It was deemed successful enough to try in our larger summer leagues. It was used on Monday and Tuesday nights during the summer of 2007 and in several of our fall offerings.

How It Works

Division of leagues into multiple tiers is no longer done. Instead, all teams are placed on one "ladder". Each team is assigned an initial rating, based on last year's performance, or some other criteria for teams with no history. For example, for this past summer's Monday league, teams that finished 2006 in tier 1 were given a rating of 1500, tier 2 teams were rated at 1450, and so on. From this point on, the league standings are based on the ratings of the teams.

Each week, the schedule is created by matching the top rated team against the second highest rated team that they have not played recently. ("Recently" normally means about four weeks, but can change depending on the league specifics.) Then, the next team down the ladder that has not yet been scheduled is assigned an opponent in the same way, and so on, until all teams have an opponent.

When game results are reported, a complex formula (based on the Elo system, see Wikipedia for more details) is used to determine the number of rating points which are transferred from the loser to the winner. The number of points transferred is based on the ratings of the two teams involved and the final score; beating a team rated above you is worth more than beating a team rated below you, and winning by a larger margin is worth more. Note that it is quite common that teams with a "better record" will be ranked below a team with a "worse record"; it's not so much whether you win, but who you beat.

Our administrators and conveners try to schedule games in rating ladder leagues about a week and a half in advance. This gives you extra time to know when and where your game is, but means that last week's results were not taken into account when this week's schedule was made.

Why It's Better

The single ladder makes it possible for teams to move up or down very quickly, which allows teams to reach their appropriate level in just a couple of games. This is an improvement over tiered systems, where new teams or teams that have had significant turnover since last year have been known to play their first round (five games) or even two rounds (ten games) against teams that are at a vastly different skill level. This has happened most commonly in lower tiers.

On a similar note, there were times where a particular tier was very competitive, but the "five week shuffle" demanded that two teams move up and two move down. When a 2-3 team moved down or a 3-2 team moved up, they were often moving into a tier where they did not have such close games as they had enjoyed. With the ladder, teams that are very competitive with each other should remain close to each other in the ladder, and end up playing each other a few times during the season. These close, competitive games and rivalries are what we all love, and what the ladder system tries to encourage.

By scheduling one week at a time instead of five weeks all at once, and eliminating all of the communications involved with organizing the shuffles, the work load for administrators and conveners is lessened and evened out. Delays at the beginning of each new round, where game locations for the first game were sometimes not known until the day of the game, are a thing of the past.

We've all had situations where injuries and vacation all seem to hit at once, and we simply cannot get enough people out to play a game. In the tiered system, if the game is to be rescheduled, it has to happen before the end of the round. In a ladder system, that game can be replayed any time (although, earlier is better, so that the results can be taken into account in future scheduling).

Future

There are certain leagues where we will continue to use the familiar round-robin scheduling, including small leagues (those with 6 or 8 teams, where the benefits of the ladder don't come into play) and our popular Thursday indoor hat league (where teams are expected to be very close in skill level). However, the benefits we have seen so far, and the mainly positive feedback we have had from administrators, conveners, captains and players, mean that the ratings ladder will be used for more leagues (including all four summer nights) in 2008.