Rating, Statistics & Leaderboard
JustGammon presents several kinds of numbers. Rating JG estimates competitive performance, while personal, community, live, and current-game statistics describe different parts of play.
Rating JG
Section titled “Rating JG”Every human player begins with a Rating JG of 1000. Rating JG changes after a recorded game between two human players has a valid winner and a single, gammon, or backgammon result.
- The winner gains rating points and the loser loses the same number.
- Bot games do not change Rating JG.
- The change depends on the difference between the two players’ ratings. Defeating a higher-rated opponent generally awards more points than defeating a lower-rated opponent.
- The result is weighted by the points awarded: a single win uses a factor of 1, a gammon 1.25, and a backgammon 1.5.
- Rating JG is unrelated to Premium, additional game balances, dice totals, or how long a player has been registered.
How the change is calculated
Section titled “How the change is calculated”JustGammon first calculates the winner’s expected result from the difference between the two ratings, using the standard rating scale of 400 points. It then calculates:
rating change = round(32 × (1 − expected result) × result factor)
The result is rounded to the nearest whole point. The result factor is 1 for a single win, 1.25 for a gammon, and 1.5 for a backgammon. This means the size of the change reflects both the relative ratings and how the game was won.
Where your rating appears
Section titled “Where your rating appears”Your Rating JG appears on the home screen and in My Profile. It can also appear in player details shown during a game.
A badge such as #3 is a leaderboard position. It is separate from the numerical rating. A player can have a Rating JG before qualifying for the leaderboard.
JG leaderboard
Section titled “JG leaderboard”Open Community stats & leaderboards from the statistics button in the application header, then select the JG leaderboard tab.
The leaderboard lists eligible human players across multiple pages. A player becomes eligible after completing at least one game against another person. Each entry shows:
- each player’s current public nickname;
- leaderboard position and Rating JG;
- a country flag when the player has selected a country.
Use the previous and next page buttons to browse beyond the first 15 positions. The Go to my position button opens the page containing your rank; if you have not yet completed a game against another person, it explains why you are not ranked. Bots and players who have played only against bots are excluded.
Your own rank can appear on the home screen and in My Profile even when it is outside the top 15. A compact rank badge for another player may appear only when that player is in the first 15 positions. Players with the same rating can still occupy different numbered positions; the position number does not imply a rating difference when the displayed ratings are equal.
Ratings are saved when eligible game results are processed. A ranking view may briefly show an earlier position until it refreshes.
Community statistics
Section titled “Community statistics”The General statistics tab in Community stats & leaderboards summarizes play across JustGammon.
Live activity
Section titled “Live activity”- Players online — users currently connected to JustGammon
- Games in progress — games currently active on the server
Live activity refreshes regularly and can change while the dialog is open.
Completed-game totals
Section titled “Completed-game totals”The community overview can include:
- games finished, total playing time, and average game length;
- games between two people and games against the bot;
- single, gammon, and backgammon wins;
- games associated with Web, Android, iOS, and console clients;
- games played to the finish, abandoned games, and timed-out games;
- total dice rolls, total pips rolled, and the actual average per die compared with the theoretical average.
These totals are calculated from recorded game history and update every few minutes. They are not expected to change immediately when a game finishes.
Personal player statistics
Section titled “Personal player statistics”Open My Profile → Statistics to review your accumulated completed-game statistics. During a game, activate a human player’s profile image to open player details. This compact view identifies the player and country, provides an accessible description of the player’s board theme, and can show Rating JG, a rank when the player is in the first 15 positions, games, wins, win rate, and wins as White or Black. Bot profiles do not open this view.
Depending on the available history, personal statistics can include:
- games played, wins, losses, and win rate;
- total playing time and average game length;
- wins as White and wins as Black;
- single, gammon, and backgammon wins;
- games against people and against the bot;
- games by platform;
- dice rolls, total pips rolled, and average per die.
Personal statistics are prepared from recorded completed games. A new player may have no statistics yet, and recently completed games may take a short time to appear.
Current-game statistics
Section titled “Current-game statistics”Current-game statistics describe the board and game you are playing now. They can include pip counts, checkers in the home board, borne-off and vulnerable checkers, hits, dice averages, doubles, dice totals, and movement efficiency.
Open the current-game statistics dialog from the game interface or press Shift+S while using the board keyboard controls. These figures are not the same as your Rating JG, personal history, or community totals.
How the four views differ
Section titled “How the four views differ”| View | What it describes |
|---|---|
| Rating JG and leaderboard | Competitive results between human players |
| Personal statistics | A player’s accumulated recorded game history |
| Community statistics | Aggregate and live activity across JustGammon |
| Current-game statistics | The board and dice information for the game currently being played |