Local Ratings

WinTD allows for two ratings on a player's record: a main rating and a second (or "local") rating. You can choose to define these however you want, however, typically the main rating is from US Chess or FIDE. You can, however, manage your own "rating system" which will fill in the second 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 rating.

If you are running a rated tournament (US Chess or FIDE), note that there are rules which control how you can use rating information outside the official ratings. For instance, in a US Chess-rated tournament, no matter how confident you are in your local ratings, you should not choose Second Rating, Main if None for assigning pairing numbers in the Ratings Tab of the Add/Edit a Section dialog box. This might end up assigning someone a rating lower than their last published US Chess value, which is contrary to US Chess rules. You are, however, allowed to use Main Rating, Local if Unrated which will use your local rating for a US Chess unrated and assign him a pairing number as if he had a US Chess rating. You can also use Higher Rating since that only overrides the US Chess rating if the local rating is higher, which is permitted.

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 Main Rating for a player with that, but no "local" rating. For players with no previous rating at all, you have two ways to handle this:

a.You can assign prior ratings yourself, based perhaps on age. We would recommend a standard deviation of 250 or 300. The Edit>Change Common Info... operation allows you to set local ratings of all players that you select in the window.

b.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. That's shown in the Average Rating for Unrateds box in the Rate Section dialog box. An alternative to that is to use a standard value for a section of a particular type (such as 500 for a section with most players around age 10; 900 for a section with high school players).

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, US Chess for computing (approximate) post tournament ratings for US Chess-rated tournaments and FIDE for (approximate) post tournament FIDE ratings.

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 US Chess 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 US Chess-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.