Systematic review guide

The second stage of the screening process involves reviewing the full text of the articles remaining after title and abstract screening. You will need to check each report to determine if it meets inclusion criteria. It is essential to keep a log of excluded studies with reasons for exclusion.

EndNote has a "Find Full-Text" feature to retrieve full text. The instructions for this can be find in our Find full text  section of our EndNote guide.
The Find full text feature won’t find all the articles, but it should retrieve a large majority of them. This works best if you are able to be on site when using it. 

If EndNote does not have the full text try Imperial Library Search or open access versions. To find open access articles try the Unpaywall for Chrome browsers and the Open Access Button Chrome downloads (or  copy and paste details of the article in the search box on the Open Access Button webpage).  

For remaining material, place a Document Delivery request with Library Services. Imperial staff and students and affiliated NHS users get free and unlimited Document Delivery requests. Click on the ‘order a book or article’ link above the search box in Library Search to place your request. Alternatively, if you click on find at Imperial next to the article’s reference on the relevant database e.g. EMBASE, this will populate the form with the article’s details for you.  

Once you have found the full text of your articles, you may wish to attach them as PDFs to the article records in your Reference Management software.  

• If you are using Endnote, then Find Full Text should already have attached most of the pdfs to your library. Please refer to the Importing PDFs section of our EndNote guide for details of how to attach any extra files.  

• If you are using Mendeley, highlight the citation to which you wish to add a document and scroll down the Details tab (right column) to the files section and click on ‘add files.’ 

• If you are using RefWorks, please refer to the  Adding references section of our RefWorks guide for guidance on attaching PDFs to article records. 

• If you are using Zotero, highlight the citation to which you want to add a document and then click the “Add Attachment” paperclip button at the top of the centre column. Select either “Attached Stored Copy of File…” or “Attach Link to File…”  

Just like ti/ab screening, the full-text screening process is designed to reduce bias and be reported transparently. As with ti/ab screening:

• use Covidence or a similar software product to manage your workflows and record reporting items. 

• full-text screening should be performed by multiple reviewers independently to reduce bias

• ensure your screening process is blinded, meaning other reviewers should be unable to see your “votes” until they have cast their own, and vice versa. Covidence has this built into its workflow

• agree on a conflict resolution protocol before screening

• once there is a reason to exclude an article, you do not need to finish reading and screening 

• if there are conflicts at the end of the screening process, reviewers can discuss the disagreements until a decision on inclusion or exclusion is reached. Another reviewer can be used to resolve conflicts if agreement can’t be reached

• Do not move on to any data extraction or quality assessment until you have fully completed full-text screening, including resolving conflicts. 

Differences from ti/ab screening:

• As well as your inclusion or exclusion decisions, the details of each report or article you exclude must be recorded along with the reason for the exclusion. Covidence will record these exclusion criteria and automatically update the review's internal PRISMA flowchart. 

• The Cochrane Handbook notes, “Systematic reviews typically should seek to include all relevant participants who have been included in eligible study designs of the relevant interventions and had the outcomes of interest measured. Reviews must not exclude studies solely on the basis of reporting of the outcome data, since this may introduce bias due to selective outcome reporting and risk undermining the systematic review process. While such studies cannot be included in meta-analyses, the implications of their omission should be considered. Note that studies may legitimately be excluded because outcomes were not measured.”  

The "included" articles remaining can now move forward to data extraction, quality assessment and further analysis.