BGA doesnt use XG engine but the same prnciples apply: In XG (eXtreme Gammon), your Performance Rating (PR) is calculated as

500 times the average equity lost per decision. A lower PR indicates a better performance, representing fewer errors compared to the perfect moves identified by the computer program. XG excludes "obvious" decisions and equity-changing cube plays from the calculation of the average equity lost to provide a clearer picture of your skill.

Here's a breakdown of the calculation:

Identify non-obvious decisions: The software identifies moves that are not considered obvious by the computer.

Calculate equity lost: For each of these decisions, the program determines the difference in equity between the move you made and the perfect move it would have made.

Sum the equity lost: The total equity lost from all these decisions is added up.

Divide by the number of decisions: This total equity loss is then divided by the number of non-obvious decisions.

Multiply by 500: The result is then multiplied by 500 to get your PR.

What your PR means:

A low PR (e.g., 2 to 3) indicates a very strong player, while a PR of 10-11 might represent an average player in the intermediate division.

This metric serves as a benchmark for your skill and is a widely accepted way to measure performance in backgammon.

You can use Backgammon Galaxy to analyze your matches using XG and get your PR.

Yani Yazdi (yani4backgammon) there is an existing feedback request to exclude these type of short matches from your PR record. When I get a moment I'll merge this one so you'll be notified if/when it's implemented.

It was only 1 move, and it was a big blunder. What to calculate ?