Systematic Search for Systematic Review

Now you have all references placed in respective groups, and the database name has been added to each record. You are ready to remove the duplicate records.

• If you need to record the number of duplicates removed from each database, we suggest you start from removing internal duplicates (within one single database), and then external duplicates (across databases).
• If you just need the number of duplicates removed from all databases, you may jump to the steps of removing external duplicates.

Follow the steps below:

Remove Internal Duplicates (within one database)

1. SAVE A BACKUP of your library, in case anything goes wrong. Go to File > Save a Copy.
2. Create a new library to store duplicates. Go to File > New. Name the library as "Duplicates". After the duplicates are identified, you will keep a copy of them in this Duplicates library, in case you need them back. (note: To facilitate this action better, create a 'Z-Duplicates' Group in the current Library.)
3. Select a group (database), then go to Library > Find Duplicates. (Note: In EndNote X9 or earlier versions, go to References > Find Duplicates instead)
   Notes  At this stage you will need to remove internal duplicates one database at a time. If you do not select a group, you are looking at duplicates across all groups (databases).
4. You will then be asked to review the duplicate record one by one. To review duplicates in one go, click "Cancel". All duplicates will then be highlighted. 
5. Now you can review the duplicates by scanning the title, authors, page numbers, etc. and de-select those that are not duplicates. Holding Ctrl key while you select or de-select any reference. (In case you lose the selection of all duplicates, go to Library > Find Duplicates, and click "Cancel" again.)
6. After that, drag and drop all highlighted duplicates to your "Z - Duplicates" group. Now you may record the number of duplicates removed and the number of remaining references in the database.
7. Last step is to move these duplicates to your Duplicates library. Select all duplicates, right-click and click "Copy". Then go to your Duplicate library, create a group (e.g. "Medline Dups"), and paste all duplicates in the group. This serves as a backup in case you need these references back. 

Now you have removed internal duplicates from one database. Repeat the process for the next set of results from another database.

Remove External Duplicates (across databases)

The steps are similar to the internal duplicates removal process, just that you do not need to select a group before finding the duplicates.

1. SAVE A BACKUP of your library, in case anything goes wrong. Go to File > Save a Copy.
2. Create a new library to store duplicates. Go to File > New. Name the library as "Duplicates". After the duplicates are identified, you will keep a copy of them in this Duplicates library, in case you need them back.
3. Go to Library > Find Duplicates (Or go to References > Find Duplicates in EndNote X9 or earlier versions). This helps you find duplicates across all databases in your library.
4. You will then be asked to review the duplicate record one by one. To review duplicates in one go, click "Cancel". All duplicates will then be highlighted.
5. Now you can review the duplicates by scanning the title, authors, page numbers, etc. and de-select those that are not duplicates. Holding Ctrl key while you select or de-select any reference. (In case you lose the selection of all duplicates, go to Library > Find Duplicates, and click "Cancel" again.)
6. After that, drag and drop all highlighted duplicates to your "Z - Duplicates" group. Now you may record the number of duplicates removed and the number of remaining references in all included databases.
7. Last step is to move these duplicates to your Duplicates library. Select all duplicates, right-click and click "Copy". Then go to your Duplicate library, create a group (e.g. "Dups across databases"), and paste all duplicates in the group. This serves as a backup in case you need these references back.