Similar items in the collection are treated as duplicates, but they are not

edited January 14, 2018
I have a couple of book entries with the same `Author`, `Title`, `Publisher` and `Place` fields, belonging to the same series. Fields `Date`, `Volume` and `Archive` are different. However, Zotero 5.0.34 treats all of them as duplicates. Ususally, assigning proper ISBN numbers resolved this problem in the past, but this time the books are old and no ISBN/ISSN/DOI has been issued.

According to, these books should not be treated as duplicates (different years):

"Zotero currently uses the the title, DOI, and ISBN fields to determine duplicates. If these fields match (or are absent), Zotero also compares the years of publication (if they are within a year of each other) and author/creator lists (if at least one author last name plus first initial matches) to determine duplicates. The algorithm will be improved in the future to incorporate other fields."

I don't understand at this point how to overcome this Zotero's behavior and get these items excluded from the duplicate list they clearly don't belong to. Also, even if the years were the same, isn't a different volume is already an explicit sign that this is not a duplicate?

  • There isn’t currently a way to mark non-duplicates—an option to do so is planned for a future version.

    In general, the Duplicates view exists to make it easier for you to find and merge duplicates. It’s not really a big deal to leave items in the list if they aren’t duplicates, and I wouldn’t worry about it.
  • @bwiernik

    I guess I just like to keep that duplicates folder clean. And it would be nice if an algorithm behind determining dupes were less limited. If it's hard to achieve now, why not just let users manually resolve the issue? This would reduce the number of WTF-moments (at least it was for me) and improve overall experience:)
  • The ability to mark items as non-duplicates isn't missing by design but simply hasn't been implemented yet. Ticket is here:
  • FYI, same issue here, but not with books.
    I have two articles with same title, and same year of publication. Everything else is different: authors, journal title, doi, issn, volume, pages, month and day of publication, etc.

    Those two articles are in the same sub-collection.
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