Stratification in ACBL games – how is my stratum determined?
Stratification is based on the distribution of masterpoints among players in that specific tournament.
In general:
- The top third (by total masterpoints per pair, or per player in individual games) is assigned to Stratum A
- The middle third to Stratum B
- The bottom third to Stratum C
A few factors can affect your placement:
- Players without an ACBL number on file or those playing with virtual partners are automatically placed in Stratum A, to prevent experienced players from being assigned to lower strata unfairly. If many such pairs are in the field, they may occupy a large portion of the A spots, shifting others downward.
- In limited-point games (e.g., 0–299 games), the top stratum is still formed from the highest-ranked players — but within that limited range. So your stratum may differ from what you’d expect in an open game.
Stratification is relative to the field you're playing in, not based on fixed point cutoffs — so it can change from game to game depending on who else is entered.
If you don’t have your ACBL number on file, we recommend updating it in your BBO account. This allows our systems to place you more accurately in the appropriate stratum. You can update your ACBL number here: https://www.bridgebase.com/mp/orgpoints/update_acbl.php