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Use RefWorks to Track & Remove Duplicates: Basic Rules

In this guide you will learn how to search for internal and external duplicates, remove them, and record in the Excel workbook.

Best Practices!

This guide was developed with systematic reviews in mind, but the process is certainly valid for anyone who uses RefWorks.  It's a good idea to get duplicate items out of your everyday RefWorks account-- you can always save an item that is already in RefWorks into a new folder for a new paper.

But-- if you are working on a systematic review, you need to follow the guidelines presented here. 

Note: You should have a new RefWorks account that has been customized and with the designated folders already created. If you have not done that yet, be sure to look at Prepare Your RefWorks Account for a Systematic Review before going any further.

Pick a database that is your primary database.  Your primary database should be the first database you search.  Whenever a duplicate is found between it and another database, the duplicate in the other database is the one that is deleted. 

  1. Check for duplicates after each and every import into RefWorks, even the first.
  2. Have a friend help you review potential duplicates; don’t do it alone if you have a large number of citations after importing from the 2nd or 3rd database.
    • Helpful Tip!  One person should check page numbers; the other needs to scan folders to make certain there aren’t any internal duplicates and to make sure the right folder (the last imported) is on top.  The 2nd person should also scan titles.
  3. Check for Exact Duplicates first, then Close Duplicates, regardless of whether you are checking for internal or external duplicates.
    • It's easier to delete the review exact duplicates as they really are true duplicates (i.e. true positives) and you will most likely delete all of the duplicates found using Excat Duplicates. 
    • Do the easy part first, if for no other reason then the sense of accomplishment.  Close duplicates is sometimes a little harder as you will have many more false positives mixed in with the true positives!

Internal vs. External Duplicates

What is the difference between an internal and an external duplicate?

Internal duplicates are duplicates that are found within the same database.

  • How does this happen? Database vendors (the people that create the interface) get updates from the actual producer of the database.  The updates include corrections to records in the current database that the vendor already has.  The database vendor just adds the records without going through a de-duping process.
  • Where should you look for this? It has been our experience that Ovid Medline and Ovid Embase are the two databases most likely to have internal duplicates. We have not searched every database from every vendor, so it doesn't mean that it can't or doesn't happen with others.  But be certain you check for internal duplicates when looking for duplicates.

External duplicates are duplicates that are found when you compare results between two databases.  One duplicate is found in one database, the other duplicate is found in the other database.

Remember-- you should check for internal duplicates EACH time you import from a database!