Score Against Common Opponents

This is a way of breaking ties by comparing the results of the tied players only against opponents they all played; the one with the better record is the winner. As a practical matter, you probably need a five round or better tournament, otherwise there may not be common opponents.

SACO will usually have the opposite result of Direct Comparison, as the games between the tied players do not count.

SACO doesn't always break the tie.

Example

#  Name        R1    R2    R3    R4    R5    R6    R7    R8   Pt    SOS    SACO  Iterated
1. Player A    12+   4+    7+    2+    3-    5+    6+    8+    7     38    5
2. Player B    5+    3+    8+    1-    6+    7+    4+    13+   7     38    6
3. Player C    9+    2-    12+   8+    1+    4-    7+    6-    5     39    1
4. Player D    13+   1-    5+    6-    11+   3+    2-    7+    5     39    0     1
5. Player E    2-    9+    4-    12+   10+   1-    11+   14+   5     36    0     1
6. Player F    15+   7-    11+   4+    2-    14+   1-    3+    5     35    0     1

Players A and B played each other, and both played all the players in place 3-8. Player B won all those games, while player A lost one of them, thus player B has the better SACO.

The players in places 3-6 are also tied, and all of them played against both player A and player B. Player C was the only one to win one of those games, and thus has better SACO than the others.

If we want, we can iterate SACO, much like we can with Direct Comparison, by calculating the SACO for the players still tied for places 4-6, who all played against the player that finished 11th. The iteration does not resolve the tie in this case, as all players won that game.