We allow for two ratings on a player's record: a main rating and a "local" rating. You can choose to define these however you want, however, typically the main rating is the USCF. You can, however, manage your own "rating system" which will fill in the local rating fields on a Master Player file.
What's the point of computing local ratings? This is obvious if you run any unrated tournaments. It allows you to take advantage of the ratings-based Swiss System, rather than relying on random or arbitrary pairing orders for the players. If you run rated tournaments with many unrated players, it allows you to rate players whose strength is at least partially known from earlier results, even though they do not yet have an official USCF rating.
If you are running a USCF-rated tournament, no matter how confident you are in your local ratings, you should not choose the Local Rating, USCF if none option for assigning pairing numbers in the Add/Edit a Section dialog box. This might end up assigning someone a rating lower than their last published USCF value, which is contrary to USCF rules. You are, however, allowed to use USCF Rating, Local if Unrated which will use your local rating for a USCF unrated and assign him a pairing number as if he had a USCF rating. You can also use Higher of USCF and Local Rating.
The calculations described here are used in two operations within WinTD: the operation Section-Compute Approx Ratings computes "post" and "performance ratings" which can be displayed in a Players Window, and Master(Player)-Update From Tournament updates the local ratings fields on a master list based upon tournament results.
In order for the calculations to work, it is necessary to have "prior" estimates of the ratings for the players. WinTD will use the USCF rating for a player with a USCF rating but no local rating. For previously unrated players, you have two ways to handle this:
- You can assign prior ratings yourself, based perhaps on age. We would recommend a standard deviation of 250 or 300. The Change Common Info... operation on the Edit menu allows you to set local ratings of all players that you select in the window.
- You can use an "average" rating that WinTD computes using the tournament information. To compute this, WinTD looks at games between unrated and rated players and determines a (single) rating for the unrateds which is compatible with their performance. When WinTD does the calculations, it will pop up a dialog box such as this:
You can accept or modify WinTD's estimate of the average strength of the unrateds (this is computed by seeing how the unrateds do, on average, with their games against rated players). One way of handling this is use a standard value for sections of a particular type, where the players would be a relatively standard age.
Note that if a small percentage of the players (fewer than 1/3) are unrated, the computed ratings won't be very sensitive to the prior ratings assigned to the unrateds.
You have to decide which of the three rating formulas you want to use. We recommend the 2P formula for maintaining a local rating system, and USCF for computing (approximate) post tournament ratings for USCF-rated tournaments. (Of course, given how quickly ratings are now updated by USCF, there probably is no reason to compute and post those any longer).
To update local ratings based upon a tournament you directed using WinTD, you need to have a master file which includes all the players from the tournament. WinTD computes new ratings based upon the information in the master file plus the tournament results. It does not use the ratings in the tournament file itself. Those may have been out-of-date when the tournament was run.
Under the USCF rating system, the Lowest Rating Allowed is 100. You might find that you need a smaller value if you have players starting even younger and weaker than would be typical for a USCF-rated tournament---if you stick with the 100, you may end up with a large number of players at that point, even though some have demonstrated better results than others.