The "Boolean Condition:" field is optional. If you wish, you can use this field to control exactly which sites you want to appear within a cluster. A condition entered into this field should be composed of terms joined by the operators "and", "or", "not". Each term indicates how many of a particular site you require: "3A" means three occurrences of site A, whereas "2(ABC)" means that you want the total number of occurrrences of A, B, and C to be at least 2. When there are multiple operators, you can use parentheses to group the terms in the expression.

Example Meaning

A and B
at least one occurrence of A and at least one occurrence of B

2A or 3(BC)
either: at least two A's; or: at least three of B or C in any combination (e.g. BBB or CBC or BBC)

(B or 3C) and not A
either at least one B, or at least three C's; but don't return any clusters that contain A

3C and not 5C
exactly 3 or 4 occurrences of C

Example	Meaning
A and B	at least one occurrence of A and at least one occurrence of B
2A or 3(BC)	either: at least two A's; or: at least three of B or C in any combination (e.g. BBB or CBC or BBC)
(B or 3C) and not A	either at least one B, or at least three C's; but don't return any clusters that contain A
3C and not 5C	exactly 3 or 4 occurrences of C