If you want to understand how good a backgammon player really is, wins and losses do not always give you the complete answer.
A player may win a match while making several weak decisions throughout the game. On the other hand, a player may lose a match while making one of their best decision-making performances.
This is where two important names enter the world of modern backgammon: XG and BMAB.
XG analyzes the game and shows how far a player's decisions are from the best possible choices. BMAB also uses this type of analysis, within a defined set of rules and conditions, to officially evaluate player performance and award levels and titles.
But what exactly is XG? What does PR mean? What is EP? How does BMAB evaluate a player? And when someone says a player has PR = 3.50, what exactly does that number represent?
Let's start from the basics.
What Is XG?
XG stands for eXtreme Gammon, one of the best-known backgammon analysis programs.
XG is used to evaluate the quality of a player's decisions and compare different positions and choices. After a game is recorded, XG can show how far a player's move was from the optimal choice, how their Cube decisions were, and the overall quality of their performance in the match.
So XG is not just a bot for playing backgammon. Players also use it as a training and analysis tool to identify patterns in their mistakes.
What Is Equity Loss?
To understand PR, we first need to understand the concept of Equity Loss.
Every position in backgammon has a certain amount of Equity, meaning the expected value of that position for a player. When a player chooses a move that has less value than XG's best choice, they lose some Equity.
XG evaluates this difference in decisions that can be measured. Therefore, the mistake itself is not the only important factor. The severity of the mistake matters as well.
One decision may lose a very small amount of Equity, while a Blunder can cause a much greater loss.
What Is PR?
PR stands for Performance Rating.
PR is a number that summarizes the quality of a player's decisions throughout a game. In XG's definition, this number is obtained from the average Equity lost per decision and multiplied by 500. Only decisions that are not obvious from XG's perspective are included in this calculation.
The important point is that a lower PR is better.
For example, PR = 3.20 is better by this measure than PR = 7.80 because it shows that the player lost less Equity on average in measurable decisions.
How Is PR Calculated?
The general calculation is:
PR = average Equity lost per decision × 500
Of course, not every move in a game is included in the calculation. XG excludes certain forced or obvious moves and focuses on choices where there were genuinely multiple options.
That is why PR does not simply count the number of mistakes. The severity of the errors also affects the result.
Why Is PR Different From Wins and Losses?
Suppose two players play a 7-point match.
Player A wins, but makes several weak decisions during the match. Player B loses the match, but makes most of their decisions close to the optimal choice.
The match result says that A won, but XG analysis may show that B made more accurate decisions.
This is not a contradiction. Match results and decision quality are two different things. The dice, gammons, backgammons, doubles, and match conditions affect the result. PR attempts to evaluate the quality of the player's own decisions separately.
What Is the Difference Between Checker Play and Cube Play?
An XG report is not just one overall number. A player's performance can also be evaluated in different areas.
Checker Play: decisions involving checker moves
Cube Play: decisions involving Double, Take, and Pass
Therefore, a player may perform well in checker moves but be weaker in Cube decisions.
For example, BMAB reports can show the PR for checker moves, the PR for Cube decisions, and the overall PR separately. If a player's checker-play PR is 4.60 and their Cube PR is 7.43, the difference between these two areas indicates that Cube decisions are where they need more practice.
This is where PR becomes more than a simple number and turns into a training tool.
What Is BMAB?
BMAB stands for Backgammon Masters Awarding Body, an organization that defines and awards Mastership titles and Proficiency Levels to backgammon players based on their technical performance.
BMAB is not a game analysis engine. Put very simply, XG is the analysis tool, while BMAB is the framework for evaluation and awarding titles.
How Does BMAB Evaluate a Player?
For a match to qualify for BMAB evaluation, specific conditions must be met. Under the current BMAB rules, qualifying matches must be played live, be timed, be arranged in advance, and be at least 7 points long.
The games are also recorded and Transcribed. BMAB then analyzes the game files using the current version of XG and specified settings.
BMAB's stated method includes Standard World Class Analysis with a Gigantic search interval, a 15×8 Bearoff database, and calculation of errors related to Resignation. Each match is analyzed at least twice, and the file with the lower overall PR is used for the first stage. In the next stage, the video and Transcription are also reviewed.
As a result, an official BMAB PR should not be directly compared with any PR number obtained from a personal XG analysis without considering the analysis method and settings.
Why Are Games Recorded on Video?
If PR is going to be part of the process for receiving an official title, it must be clear that the game file actually corresponds to the same match.
The process can be summarized as follows:
Video: recording the actual game
Transcription: converting the game into an analyzable file
XG: analyzing decisions
BMAB: reviewing the game and conditions and determining the level or title
What Is EP?
EP stands for Experience Points.
In the BMAB system, EP is equal to the total length of qualifying matches. For example, a 7-point match generates 7 EP, while an 11-point match generates 11 EP.
This measure is important because a single outstanding game does not provide a complete picture of a player's level.
Under the current BMAB evaluation system, before reaching 300 EP, the PR average is calculated based on the history of recorded games. After reaching 300 EP, the PR average is calculated based on the most recent matches up to a total of 300 EP. A match that crosses the 300 EP threshold is included in full in the calculation for that window.
Master and Grandmaster Levels in BMAB
BMAB has defined several levels for Mastership. The current criteria include a target PR and a minimum EP requirement.
Master 3: PR of 6.50 or lower and at least 100 EP
Master 2: PR of 5.50 or lower and at least 100 EP
Master 1: PR of 4.75 or lower and at least 100 EP
Grandmaster 3: PR of 4.00 or lower and at least 150 EP
Grandmaster 2: PR of 3.50 or lower and at least 200 EP
Grandmaster 1: PR of 3.00 or lower and at least 250 EP
Grandmaster 0: PR of 2.75 or lower and at least 300 EP
Therefore, a PR of 4.00 in a single match does not by itself mean that a player receives the Grandmaster 3 title. The BMAB criteria also consider accumulated performance and minimum EP.
What Are Advanced and Intermediate?
Advanced and Intermediate are part of the Proficiency Levels.
Advanced 1: PR of 7.50 or lower and at least 100 EP
Advanced 2: PR of 8.50 or lower and at least 100 EP
Advanced 3: PR of 10.00 or lower and at least 100 EP
Intermediate 1: PR of 12.00 or lower and at least 100 EP
Intermediate 2: PR of 14.00 or lower and at least 100 EP
Intermediate 3: PR of 16.00 or lower and at least 100 EP
Within the Mastership section, Super Grandmaster levels rank above Grandmaster.
Super Grandmaster 3: PR of 2.50 or lower and at least 300 EP
Super Grandmaster 2: PR of 2.25 or lower and at least 300 EP
Super Grandmaster 1: PR of 2.00 or lower and at least 300 EP
So What Is a Good PR?
For general understanding, a lower PR indicates less Equity lost in measurable decisions. However, a PR number should not be considered an absolute measure of skill without considering the number of games, EP, and analysis settings.
For example, a player may record PR = 1.90 in one match, but that number alone is not enough to compare them with a player who has a much larger volume of games.
In the BMAB system, official titles also depend on a combination of PR and EP.
How Is PR Different From Elo?
PR and Elo are two different metrics.
PR evaluates a player's decision quality relative to analytical choices. Elo is used to rank players based on their results and competitive performance against other players.
Therefore, a player may lose a match while recording a better PR than their opponent. In this situation, the match result and decision quality provide different information.
Does PR Show Everything About a Player?
No. PR is a useful metric for evaluating decision quality, but it does not capture every skill a player has in a single number.
Time management, match conditions, tournament experience, knowledge of the opponent, and strategic choices also play a role in a player's performance.
Even a very good PR in a short match does not necessarily mean that the player's overall level has changed. The larger the sample size, the more complete the picture of their performance becomes.
Why Do Professional Players Try to Lower Their PR?
For a player who wants to improve, the main question is not simply how many matches they have won. The more important question is how well they made their decisions.
PR helps identify patterns in mistakes:
In what situations do I make the most mistakes?
Are my mistakes mostly related to Checker Play or Cube Play?
Do I repeatedly make the same type of error?
Is my improvement in PR consistent, or have I simply had a few good results?
How Can We Use XG to Improve?
The worst way to use XG is to look at the PR number after every match and say, “Today I got 5.8” or “Today I got 9.”
XG becomes much more valuable as a training tool when you review your mistakes.
Play without assistance first. Make your own decisions before looking at the analysis.
Record the game. You will need the same file later to review your decisions.
Find the important mistakes. Especially Blunders and decisions that are far from XG's choice.
Think again before seeing XG's answer. Ask yourself what you would do if you returned to the same position and why.
Find the reason behind XG's decision. The goal is not to memorize the engine's move. You should understand the logic behind the decision.
Categorize your mistakes. For example, Prime, Blitz, Backgame, Race, Holding Game, Anchor, Cube, Take/Pass, and Bearoff.
After a while, you will see patterns in your own mistakes. You may discover that most of your errors are in Cube decisions or that you have problems with Race and Bearoff positions. From this point onward, your practice becomes more targeted.
So When Someone Says “My PR Is 3,” What Exactly Does That Mean?
That statement alone does not provide complete information.
To interpret it correctly, we need to know how many matches the PR covers, how much EP has been recorded, what analysis settings were used, and whether the number comes from a regular XG analysis or the official BMAB process.
It should also be clear whether the number is the overall PR or only the PR for Checker Play or Cube Play.
Without this information, a PR number can provide an incomplete picture of a player's performance.
What Is the Difference Between XG and BMAB?
Put very simply:
XG: a tool for analyzing the game and a player's decisions.
Equity Loss: shows the amount of value lost as a result of a weak choice.
PR: summarizes the average quality of measurable decisions in a single number. Lower is better.
EP: represents the volume of qualifying matches in the BMAB system.
BMAB: evaluates PR, EP, and official conditions to determine levels and titles.
Ultimately, winning a match tells you who won; PR helps you see how close the player's decisions were to the optimal choices.
The two do not always show the same thing, and this difference is one of the most fascinating aspects of modern backgammon analysis.