ChessWorld - Rating System FAQ's

In the first 50 games, your rating is 'provisional' and is calculated by using a standard robust and proven performance rating system - namely the English Chess Federation rating system. This performance-based rating system ensures, for example, that you cannot gain points from losing against a much stronger player, or lose points by winning against a much weaker player.

After the first 50 games, due to the way averaging works, the rating would become frozen eventually, and therefore there is a requirement to use a different method for rating calculation. From your 51st rated game onwards, the 'Elo' rating system is used.

The Elo rating system is the basis of Worldwide standard established FIDE and USCF ratings in Over-the-Board chess. It is a proven method of rating players based on the difference of ratings of the two players, and their score. i.e. 0 for a loss, 1/2 for a draw, 1 for a win. The particular Elo Formula based on 'normal' distribution is:-

Let us say that your rating is r1 and the opponent's rating is r2. Let w have the value of 0 if you lose, 0.5 if you draw, and 1 if you win. The final, and most important, factor is the value of K - this is set according to your rating and special considerations such as if the opponent is provisionally rated or not. The formula may be expressed mathematically as follows:-

                                                                            1
                                    r1 + K * [ w   -    ---------------------------    ]
                                                                1 + 10 ^ ((r2-r1)/400)

You may wish to use the ChessWorld Elo calculator where you can enter your rating, your opponents rating, and the K-factor and then calculate your new rating.

The Elo formula, above, makes use of the classic normal distribution. By default, the K-value is based on your current rating, as follows: -

                K = 32     If your rating is less than or equal to 1600
                K = 16     If your rating is greater or equal to 3200
                For intermediate ratings,     K = 32-(r1-1600)/100

Example: Assume a personal rating of 2355.
     Using the formula above: K = 32 - [(2355 - 1600)/100] = 24.45.

However, a much simpler method is to use the ChessWorld ELO calculator and simply enter your current, personal, rating. This will automatically calculate your K rating. Using the value above the K value will be confirmed as 24.45

Special considerations when you play provisionally rated opponents

Because provisionally rated players may carry an inflated rating, we make use of a scaling down function for the K-factor based on their number of completed rated games. The scaling function is n/51 where n is the number of rated games that they have played.

You should try and focus on your overall standard of chess to improve your ChessWorld rating. You may find some good books to assist you - for example, visit the BookFinder page and check which books other Members own and which are the most instructive. You may find that the links to Books owned by members and Most Popular books are particularly helpful.

Chess is a game of skill. There are a huge number of different levels of understanding in Chess and it is possible for even strong International Chess Masters to be comprehensively beaten by top Grandmasters. Even top Grandmasters can, in turn, be demolished by players in the World Top 10 list. A rating system allows players to find evenly matched opponents or opponents slightly stronger, which can lead to more exciting two way games. The rating system can also show how strong one is relative to the overall population of ChessWorld Members.

Studying chess and practising can improve your overall rating, but there are no guarantees!

For your first 50 games your provisional rating is based on the English Chess Federation (ECF) Grading system. After the first 50 games, Elo calculations are used based on Classical Elo with a normal distribution curve.

There is a provisional rating period which applies to your first 50 rated games only.

Massive fluctuations will occur to your rating within the first few games until it settles down to reflect the performance over 50 games. Within the ECF rating system model, used in the first 50 games, there is a 'Rating roof' implication.

If you are playing someone who is very much stronger than you in the ECF model, for example, 60 ECF points higher than you, then it is assumed that the difference is exactly 40. The reason for this is not to be able to gain points by losing to someone much stronger than you. A win under the ECF model is counted as your opponents rating +50, and a loss as your opponents rating -50. If their rating was more than 50 points higher than you, then losing against them would gain you points!

On ChessWorld, 40 ECF points translates to 320 rating points. For example, if you are rating 1200 on ChessWorld, and you are playing someone rated 2700, in fact it is like you are playing someone who is  a 1520 rating. The key here is, in your provisional period, to be content with playing people that are within a 320 point rating range and no more, if you are out for maximum points by beating the big guns. Playing players any stronger will have no impact until your rating increases and then your range increases.

After the first 50 games the rating system as described in detail above applies.

Your accumulated points are being averaged by a small number of games, and hence heavy fluctuations result in the first few games. As you play more games your rating will become more and more settled. You can see this fluctuation and how your performance changes by looking at your rating graph, which you can access via My Stuff ... My Ratings.

Yes, ECF 100 is assumed for everyone. Because there are heavy fluctuations in the first few rated games as the rating settles down, it does not matter that the rating is set like this.

Yes, just set your FIDE rating to the equivalent of what your rating is. This is fair because the ratings in the first few games fluctuate heavily anyway. It allows proven strong players to be more quickly identified by the existing stronger players on the site. We may, at our discretion, ask you to provide verification of your rating.

Yes, just set your FIDE rating to less than 1400 when you first start off.

In general, no. However, if you are invited by, or choose, a site Welcomer, any games with that player will be rated.

Subject to certain criteria, ChessWorld does invite all Guest Members to specific Guest Welcoming Tournaments. These Tournaments offer players a chance to play a number of rated games.

By limiting the number of rated games available to Guest Members, it means that the rating system is less prone to distortion by an individual player creating multiple Guest Member accounts, and then using those accounts to deliberately lose games. It would be highly unlikely that someone would want to do this by using multiple Full Member accounts, which would involve a significant financial investment.

Only games longer than 10 half moves count towards ratings

ChessWorld imposes this limit in an attempt to avoid a situation where players may agree quick losses, draws or wins with each other in an attempt to manipulate their ratings.

By making this strategy more time consuming such abuse is less likely.

Exceptionally, in the extremely rare case where a game is finished by checkmate within the first 10 half moves the rating calculation is invoked. As ChessWorld records all games ending in checkmate we are able to detect potential manipulation. Any such abuse always results in appropriate action being taken in accordance with our Terms and Conditions.

Yes, Full Members can go to their My Stuff ... My Interface page and elect to have the full rating predictor implications on the play page.

Rating in Correspondence Chess can be affected by the fact that you cannot see what outside assistance your opponent is using. There are restrictions regarding acceptable assistance: refer to the section Member Assistance and Fair Play in our Terms and Conditions for further guidance.

Yes, from the Join Games ... Join New Tournaments page, you can choose to play in 'Class' tournaments and you will be paired with players with approximately the same ChessWorld rating as you.

Yes. It can happen because your rating reflected on the playing screen is not 'real time'. For example, if there is a rated result, such as someone resigning against you, and you have not yet refreshed the playing page, the calculations that are shown will be based on your previous rating. You can easily check by refreshing your screen.

Yes, if you have played less than 50 rated games you can change this setting via My Stuff ... My Details. However, once you have completed 50 rated games this descriptor is set automatically by the system and cannot be altered in any other way.

ChessWorld provides a number of different ranges for players of different ability. The playing strength for any player is shown on their homepage in the  Rating  tab. Until a player has completed 50 rated games their classification can be defined, or changed, by visiting the My Stuff ... My Details page. After the initial 50 games have been completed the Playing Strength indicator is based upon the current rating of the player and is therefore controlled solely by the ChessWorld server.

You can check the whole range of ChessWorld classifications in detail by visiting the Rating Classes page. ChessWorld also groups player ratings into the following Categories for certain Tournaments:

   Strength Tournaments:    Beginner- up to 1600,     Intermediate - 1601 - 2400,    Advanced - 2401 and above

   Class Tournaments:        A) less than 1400,    B) 1400 - 1879,    C) 1880 - 2199,    D) 2200 and above.

Every player is recorded on the ChessWorld database in rank order, from the highest rated player to the lowest. It is common practice to consider such a ranking list in simple steps of 1% to avoid having to place many players on common levels. A player placed on the 99th percentile would therefore be a player whose current rating is above 99% of the Members. A player placed on the 50th percentile would be placed in the middle of the Membership in terms of rating. In general every percentile ranking will include a wide number of players.

For a more formal definition of the term, refer to the Percentile article available in Wiki. This page covers the mathematical context and offers relevant references for those who may be interested in exploring the concept further.

You can check your own percentile ranking by visiting your Homepage and opening the   Rating   tab. Your current ranking will be shown in the last row of the top box.

The Rating Graph can be accessed from any homepage via the   Rating   tab, or via My Stuff ... My Rating by clicking the appropriate links. Be aware that the Graph shown within the Rating tab provides a basic overview and cannot be configured. By default the main Rating Graph is displayed in multiple colors to distinguish between   Win  ,   Draw   or   Loss  . The left-hand bar, (in   magenta  ), shows your current rating.

In the case of a game that has been lost on time the color of the bar changes to indicate a   Time Loss  . This is a useful guide to any player who wishes to check the general playing performance of a propective Opponent. In those cases where a player may have accumulated a large number of such results that player may be classified as a sandbagger to protect the integrity of ChessWorld Tournament play. For further details on this specifc topic please refer to Q. Why have I been marked as a sandbagger? in the Playing section of the Chess FAQ's.

As well as viewing your own performance, you can look at any other player, your next Opponent for example, by visiting their Homepage and then access their Rating Graph to get a useful indication of their performance.

The Rating graph shows you your progress, as measured by your rating, over the last 50, 100 or more, in multiples of 50 games, with the latest results at the left hand side You can choose to display your record in monochrome but using the default display highlights actual results, which helps to illustrate 'runs' of success or failure. To make your analysis simpler it is helpful, by clicking Default + Ratings, to superimpose your opponents rating so that, when combined with the multi-colour option, it is easy to determine exactly why your performance varied over time. This combined graph is probably the most suitable for analysis as minor variations in your performance, which tend to be over-emphasised in the basic graph, are reduced.

As you hover over any one of the bars in the graph, the game details are shown in the left hand panel and the final position is shown on the mini-board. If you click on the mini-board you will be taken to the actual game where you will be able to use all the normal facilities provided on the ChessWorld game board. Below the mini-board we also provide several options. View opens the board in the same window or tab, Open opens the game in a new window or tab and Share provides a page containing further information about the game which you may use to post to friends or message boards. Analyse will open the pop up version of the Analyse board and PGN provides the game details in standard PGN format which you may copy and export as you wish.

The left hand panel shows basic game details, including your opponents current rating. To check ratings at the time the game was concluded hover the mouse over the relevant bar. You will see a message such as Player's Rating: 2500, or, if you hover over the small square that represents your opponent on the graph, you will see a message such as Opponent's Rating: 2500.

There is no simple answer to this question. However, most players tend to have quite slow changes in rating so a reasonably level graph is 'normal'.

For a good general impression, look at the Rating Graph showing the results in colour and with the opponents ratings superimposed. Most 'normal' graphs tend to show that the opponents rating fluctuates above and below your own rating. It would, however, be unusual if your opponents ratings were always above, or always below, your own rating.

Most 'normal' graphs show a mixture of results, and are unlikely to show exclusively either all wins or all losses over a 50- or 100-game range.

Yes. If you wish to check performance(s) beyond the 100 game default setting go to My Stuff ... My Rating and select Opponent Statistics. On that screen, click on any of the highlighted links within the My Stats or Opponents Stats sections to display a graph covering the relevant 50 game selection.

You may also use the << Prev | List | >> Next links to move through the graphs, displaying results in 50-game increments. You may also use this link to view beyond the last 1000 games that are detailed in the My Stats or Opponents Stats sections.

If you use the Last 100 games option when viewing extended ranges the graph will be reset to display the latest 100 games only.

Yes. When you are on the Rating Graph page simply click on the Game link in the lower left corner. This will change to Date and the games will then be displayed in month order, with the latest results, for the current month, displayed at the left-hand end of the graph. Note that the month indicator is placed at the mid-point so that the results for a given month will normally be displayed equally on either side of the tick mark.

Depending upon your general activity and the number of games completed in any given month there may be some overlap. This effect will be accentuated if you finish a number of games in a given time period; equally, if you finish no games over a given time period you will see a 'gap' in the graph.

No! The ChessWorld Rating system is carefully designed to give due credit for the specific format of on-line Chess as played on the ChessWorld server. We have evolved a unique system, based upon well proven International standards, that is best suited to the demands and expectations of our Members. As such, it is quite reasonable to use your rating, once you have played more than 50 games, to give you an indication of your relative ability as compared with any given opponent on ChessWorld.

Because our system is designed specifically for ChessWorld there cannot be any meaningful comparison with the more common external measures that may be of interest. For example, ratings as awarded by ECF, FIDE and other formal bodies are based upon over-the-board, (OTB), play where it is possible to ensure carefully controlled and monitored conditions. The nature of web-based correspondence chess is such as to preclude any such controls, which cannot be replicated on this, or any other chess playing site.

In some cases, our Members may have recorded their current FIDE, or other, ratings on their homepage and you may get a very approximate comparison between that and their ChessWorld rating. However, this should not be taken as a definitive conversion.



On ChessWorld HERA represents Highest Ever Rating Achieved. This information is provided to enable you to form some idea of the current ability of your opponent.

In Mythology, of course, Hera is the wife, (and, in some versions, the sister), of Zeus.

The HERA value provides an indication of your Opponents ability at the time that it was achieved. For a more balanced indication of your Opponents ability, rather than rely solely on their HERA value, you should also check their most recent rating graphs which may show, for example, steady and consistent play, or, in some cases a slow and steady decline. Always remember that the rating of your Opponent is based upon their current activity; historical data may not be an accurate relflection of their current performance.

ChessWorld made significant improvements to the Rating system as from January 2006 and there is no direct comparison with the previous system. As such you should be aware that HERA values achieved before that date are a less reliable indicator.

It is possible that, in certain circumstances, the information displayed in the pop-up, described below, may not be up-to-date. If this occurs simply visit your Rating Information page when the pop-up value will be updated. The information shown on the Rating Information page is always correct

When you visit a play page simply roll the mouse over your name. A small pop-up will appear showing a brief summary of your performance, for example:

Statistics
Wins:500 Draws:150 Losses:400
Highest Rating achieved: 2000
Date achieved: 1/12/2006
Joined the site: 4/23/2004
Last logged in

The value of HERA shown is based upon your achievement after completing 50 rated games where this is appropriate.

The Tournament Performance Rating is often used in real-life Tournaments to provide a measure of relative performance against other players in the Tournament.

This information is provided, for completed All-play-All Tournaments, on the cross-table page in three columns, headed TPR, ER Offset and Upset. Further information is available by passing the mouse over the values in the TPR column. Depending upon which value you mouseover the results will change to reflect the performance of the chosen player.

It is important to be aware of the difference between a player Rating and their TPR. Rating is a measure of overall ability, over some specific period of time whilst TPR is calculated for a particular Tournament. A player, who may, or may not, win all of his or her games may nevertheless perform well above their Rating level against some players in the Tournament. Equally, of course, it is likely that they will also perform below that level against other players.

On ChessWorld the value of the TPR is based upon the rating achieved by a player at the conclusion of the game, (the closing Rating), and is then compared with their rating at the start of the game, (the enrolment Rating), and is independent of the game score points accumulated in the Tournament. For example, a player with a ChessWorld rating of 2100 may have a TPR of 2350, suggesting that, in the majority of their games in that Tournament, they had played better than may have been expected even though they may not have won the Tournament. Conversely, a player with a ChessWorld rating of 2000 may achieve a TPR of 1900, suggesting that they may have played below their expected level.

A positive TPR, that is, one with a positive percentage shown in the ER Offset column, is achieved when their playing performance has demonstrated that they have played 'above their rating' against a specific Opponent. Equally, a negative rating would suggest that they played less well.

How you make use of the TPR is a matter of personal choice. In many cases you may feel that a positive TPR shows that you have some success with, say, a favourite Opening; a negative TPR may suggest that you are less successful with another Opening and may benefit from further practice in a future Tournament. You also wish to compare your performance when using different methods of preparation. For example in a Tournament where you made extensive use of the Analysis board you may find that your performance was noticeably better than in a different Tournament where you used minimum preparation time.

On ChessWorld an upset is said to have happened when a player manages to beat an Opponent having a significantly higher rating than themselves. For example, a player rated at 1500 beating an Opponent rated at 1550 may be considered to be unremarkable. However, if that same player managed to beat an Opponent rated at, say, 2000, then that would be praiseworthy and would be classed as an upset.

ChessWorld may, from time to time, adjust the margin, or threshold, used to define an Upset.

You will see this term if you visit My Stuff ... My Rating and you click on the Opponent Statistics link. This page displays your own and your Opponents' playing performance in two blocks showing respectively My Stats (Max, Min, Avg, SD) and Opponent Stats (Max, Min, Avg, SD). Within each block games are grouped in batches of 50 which may help you to detect gradual changes in performance.

The first three categories should be self evident, maximum, minimum and average. However, the final value, SD, is less obvious although, in fact SD is the recognized abbreviation for the statistical term standard deviation.

As a general guide, if the SD figure is small, say, below 2, then your performance is fairly consistent. As the value increases, then it would tend to show that your performance is inconsistent in some way.

In the case of your Opponents, if the SD figure is small, say, below 2, then their ability range tends to be fairly narrow. As the values of SD get higher then it is likely that you are playing Opponents whose ratings are widely separated.

Interpreting and gaining the maximum information from SD figures can be quite challenging. For Members wishing to increase their general understanding of the concept, this Standard Deviation article, available in Wiki, provides some detailed mathematical background.

For a much less technical approach this page provides an easier and clearly presented illustration of how some simple statistics can be used.

This is done so that any Member may observe the relative performance of the players at the time that the game actually took place. To provide a point of reference, we display the current rating for each player within brackets.

It is important to bear in mind that unless the original ratings are displayed it is often difficult to fully appreciate the quality, or otherwise, of any given performance.