Net-Results Segments employ Boolean Logic to ensure that our software always builds database queries that not only work, but will execute in a reasonable amount of time. When you create a Segment, behind the scenes Net-Results is building some pretty impressive queries to select only the Contacts that qualify for the conditions you’ve chosen. It sounds complicated but it basically comes down to a combination of ANDs and ORs. That said, there are a few situations where boolean logic can be counterintuitive.
Let’s say you want to build a Segment that selects all Contacts from List A, List B and List C. You may build a Segment that looks like this:
Do you see the problem? The Segment above will only select Contacts who are members of List A and List B and List C. A Contact has to be a member of all three lists in order to qualify. This is not usually what is intended as very few Contacts will qualify, if any. Below is the correct way to build this Segment:
By using ORs rather than ANDs we end up selecting Contacts who are members of List A or List B or List C. Every Contact who is on any of these three lists will qualify for this Segment.
Below are two great graphics explaining segment logic!