A click on Search for duplicates on the participant main page will display a form asking for the criteria to search on. Criteria can be any combination of user-defined data columns.

The duplicate search will first look whether it can find values over all selected columns where there is more than one profile having all these values. For each value (set of values) that are found in more than one profile, the search will then return a list of those profiles (grouped by the values).

To give an example, you could search for duplicates on firstname and lastname. The search will look whether there are any profiles in the database that share both firstname and lastname. It will return a list with all the affected records, grouped by the respective firstname/lastname combinations.

You can then use the edit links to edit (or, unsubscribe) the affected profiles.