There are a few different criteria Crowdskout's matching algorithm looks for when trying to append two or more profiles together. Below are the criteria Crowdskout looks for:
First Name + Last Name + One unique identifier (email or address or phone)
If two profiles only have emails and the emails are the same, those two profiles will merge.
Voter ID's: if the voter id's + state registered are the same, the profiles will merge.
Additionally we match on External ID's, i.e. Salesforce ID, CMDI ID, etc.
For more information, take a look at "How Do Profiles Merge?"
If you are still seeing duplicate profiles even when all profiles have identical contact information, let your Customer Success Manager know and they can help you!