Rating calculation

[Alex Starks]

Today is regular ratings update day and I was wondering if someone will be able to clarify couple of questions for me.

I think that TD download CFC database with ratings and use that to pair players and to post list of registered players with their CFC membership numbers and ratings. Some registrations are done well in an advance and rating listed beside players name might change couple of times before tournament actually starts.

My first questions is how ofter CFC database is updated? As an example, I randomly picked Adam Adriaanse who played at 2019 Eastern Ontario Open Section. His rating at the tournament was shown as 2202 and CFC site shows his rating as 2211 as of April 29 2019.

Second questions is who is responsible - player to notify TD of his changed rating since tournament registration or TD to us the latest available CFC database and ratings to pair players.

Third question - if TD uses player's old rating and player doesn't complain about it for whatever reason, would CFC rate player using rating at the time of tournament registration or player's latest rating as it is in CFC database/web site.

The last questions is regarding rated tournaments that are held over course of 5 weeks. How is rating calculated at the end of such tournament - will rating at the start of the tournament be used, latest rating in the CFC database at the end of the tournament or something between.

[Alex Ferreira]

Hi,

From my experience, some players register for an event way in advance, others at the last minute. Many carefully submit their ratings, others don't, some don't even seem to know what their ratings are. As an organizer / arbiter, you want to make pairings with the latest published ratings. Not the ratings players registered with, which may have changed since. Irrespective of what the arbiter does, the CFC will use the latest rating update of a player's rating, and use that as a base for the tournament an organizer submits. On occasion, two tournaments played by the same player (usually one weekend tournament and one club weekday tournament) are submitted for the same rating update. I am under the impression that the tournament finishing first gets rated first.
The CFC updates its database weekly. As an organizer I register players with the current ratings at time of registration, and only change them after the last update before the actual tournament. With lots of players, it's simply too laborious to do this weekly for a couple players whose ratings change. I wouldn't put any real responsibility on the player for not being totally up-to-date with their ratings. I do ask unrated players if they've played in tournaments anywhere before, and do expect an honest answer and try to work something out from there if they did, in a different rating system.
A 5 week club tournament for example, is paired with ratings from the start of the event. I would keep these ratings throughout the same tournament, and not manually fiddle with them as these same players play 2-3 weekend events and their ratings change. This would affect their seeding and can cause discrepancies in the integrity of the swiss pairings. If a player joins a 5 week swiss tournament in Round 3, just use the player's rating when the player enters the tournament. When this tournament finishes, you can submit the tournament with the 5-week-old ratings, it's not an issue. CFC will match the players' IDs and just rate your event with their latest ratings. Which may or not correspond to the ratings you have. The players' IDs are static so the system will correct itself.
Hope that answers your questions.

Alex F.

[John Brown]

As far as I know your rating is only used for pairing Purposes. When you submit the results the paper work does not use ratings just CFC #'s. So if you can get the latest rating to use before Round one that is ideal.

[Alex Starks]

Thank you Alex for a such detailed explanation. I appreciate it.