Systematic and Other Reviews: Exporting from databases and deduplicating results

Exporting from databases and deduplicating results

This is a practical stage where you will be exporting your searches from databases, and importing them into a reference manager like EndNote. From there you can deduplicate your records.

This section will show you the process using EndNote however you can use other referencing software if you prefer. These steps (creating folders, exporting from databases, deduplicating) can be generalised.

It's important to carry out these steps carefully and to document them. You will need to record how many articles you've identified and have cut out at each stage in your PRISMA flow diagram.

Exporting from Databases

Many academic databases allow you directly export references to referencing software e.g. EndNote. Instructions on how to do this for various databases are provided below.

Make sure you double check all imported references to make sure they are formatted correctly. This is an extremely important part of the process as imported references are often not 100% accurate (you'll sometimes need to correct for missing years, titles all in upper case, missing journal volume, issue or page numbers, etc). Any uncorrected errors will be reflected in your reference lists.

Downloading Large Amounts of Records for a Systematic Review

We've made a PDF guide showing you how to download large amounts of records from various Library databases for the purposes of conducting a systematic review. Included in the guide are instructions for Cochrane Library, Ebsco, Embase, Informit, OVID, Proquest, PubMed, Scopus and Web of Science.

Creating Groups and Group Sets

Because systematic reviews require you to record the amount of results you are getting from each database you use, it's a good idea to learn how to use groups and group sets. A group set a heading under which groups are filed. For example, the group set could be named for the topic of your research, and the groups could be named for the databases you are using. 

Later, you can run the 'Find Duplicates' function on the group set to locate duplicates across the various databases used in your research
 

Creating a Group Set

• Go to Groups > Create Group Set, a new group set will appear under My Groups
• Give a name to the new Group Set: eg: Systematic Review
• You can now add groups beneath the group set, named according to the databases you are searching (Medline, Pubmed, Cinahl etc)
• You can also drag and drop Groups between different Group Sets

Creating a Group

• Go to Groups > Create Group
• Give a name to the group

Adding references into a Group

To add a reference or references, select them and then either drag them to the group or right-click on the selected references and choose Add References To.

For more detailed information on groups, see our Using Groups page (linked below)

Adding references manually

As part of your systematic review, you may want to collect grey literature, including information from websites. To do this you will have to enter some information into EndNote manually. 

The guide below shows you how to manually enter information into EndNote to make APA 7th references, using the library's APA 7th style. 

If you need to manually input references for a different referencing style, please consult the Adding References Manually page, or contact the library using the link below.

Finding and removing duplicates

When importing references from different databases, you may find that you have duplicate references in your EndNote library. The following steps show you how to find and remove these duplicates.

• Select where you want to find duplicates, e.g.: All References, or a Group or Group Set.
• Go to Library>Find Duplicates
• EndNote will present you two references at a time to compare. Any fields which are different in the two records will be highlighted.
• Decide which to keep and click the Keep This Record button. The other record will be moved to the Trash folder.

If you have a large number of duplicates and don't want to go through them one by one, you can highlight and delete all the duplicates at once. To do this, simply click Cancel in the Find Duplicates window.

The window will close, and a temporary folder named Duplicate References will be created. You will now see all the Duplicate References highlighted in green in your EndNote library.