## Combining segmentation rules

Two rules that make up a segment, such as rule A and rule B, can be combined by using the ANDOR or EXCEPT logic operators, also referred to as interaction conditions.

• AND
The result is the set of contacts that match both the first and the second rule. This is equivalent to the intersection of contacts selected by both rules.
• OR
The result is the set of contacts that match either the first or the second rule. This is equivalent to the union of contacts selected by each rule.
• EXCEPT
The result is the set of contacts that are selected by the first rule, but not by the second rule. This is equivalent of subtracting the contacts selected by rule B from those selected by rule A.

When more than two rules are used to define a segment, the system applies the interaction conditions sequentially. Plan calculates the result of combining the first and second rule. This result is then combined with the third rule, using the interaction condition between the second and third rule, and so on.