There are two kinds of duplicate searches in RefWorks:
Exact Match - checks for exact matches based upon the Author Names, Title and Year of Publication fields.
Close Match - checking is done by comparing a combination of Author Names, Title, and Year of Publication. It is a loose comparison so may result in a display of references that are not exact matches. This allows duplicates to be found even if there are minor errors in the data. Also, depending on the size of your RefWorks database, the Close Matches may take some time, so be patient.
To remove duplicates from the database:
Mark the reference you wish to delete by clicking the box next to the Ref ID. These selections are not saved when you go to the next page. So be sure to add the references to a folder before moving to another page.
Note: RefWorks automatically marks duplicates (the most recently added record) for deletion when the duplicate check is performed. If you have more than two copies of the record, only the most recently added record will be marked for deletion. You can disable this automatic selection in the Customize area under the Reference List section.
Check out the help screens for info on finding and removing duplicates.