You need to find all contacts that do not have a particular value stored in a data field. Use the <>not equal to as the IS selector when creating your segment.
- Navigate to the Contacts dashboard and choose "Segments" from the left-hand menu.
- Click the "Create Regular Segment" button at the top-right of the page.
- Give your segment a name and description.
- Open the "Select Field" drop-down and search for the database field you want to segment on (for example, City)
- Select "Not equal to" from the "is" drop down menu.
- Enter the value, for instance, Carmel.
- Click OK to insert.