Candidates: Data-Duplicate Information
As a rule, Clockwork does NOT destroy data. We never eliminate/override/delete existing data. The computer doesn't know what is important, so we keep all data.
Specifically, For most text boxes that are in Clockwork (for example: biography) - the system looks at the content within the source (what is being imported) and the target (the existing contact that is being updated) fields of information. If the data is EXACTLY the same, then the source information is ignored. If the data is not EXACTLY the same, then the source information is prepended (inserted above) the existing information.
This allows users to add to biography with more relevant information (more current biographical information) at the top. This also makes sure that the most relevant information is stored at the top of a contact record (such as when merging 2 contact records, for instance).
An Example - Duplicate Biography
You may have a LI URL where the owner of the profile has updated their "About" Section between the first time the contact was imported and the current time the contact was imported. Remember, Clockwork doesn't know what is relevant for the user between the first importation and the last, so the data is kept from both. When this happens it is likely you will see a duplicate Biography for that Candidate in your CW database.