Once you have completed your search, the next phase is to screen and select the studies to be included in your review.
The purpose of screening is to eliminate any studies that do not meet your inclusion criteria. The inclusion/ exclusion criteria would have already been decided on during the Protocol step. It is recommended and also best practice to use a team of 2-3 independent reviewers during the screening stage to reduce selection errors and selection bias (Cochrane handbook, Ch. 4.6.4).
Screening is usually completed over two phases:
This step involves scanning the title and abstract to eliminate any irrelevant results. At this stage, in most cases it is not a requirement to provide justification for removing any results.
This is a more in-depth look at the articles that passed the first phase of screening by reviewing the full text against the inclusion/ exclusion criteria. During this phase you must provide a reason for why the article has been excluded. Sometimes two reviewers will have conflicting views on whether the study meets the eligibility criteria. This why it is a good idea to have a third reviewer to resolve any conflict, therefore helping to remove bias in the selection of studies.
To assist with the screening process you may want to consider using one of the tools listed below.
Use Endnote to export search results into an EndNote library. Create groups to screen studies against the inclusion and exclusion criteria. For more information and resources for Endnote please see the VU EndNote LibGuide.
EndNoteTraining. (2021, August 25). In action: EndNote 20 (Windows) find duplicates [Video]. YouTube. https://www.youtube.com/watch?v=30hO68w0C-4
Covidence is a web based software that assists with the screening and data extraction in systematic reviews. Access to Covidence is available via subscription. There is also a limited free trial version available.
See the 'Support' section of the Covidence website for more tutorials, step-by- step guide and videos.
Covidence. (2021, October 27). Covidence demo [Video]. YouTube. https://www.youtube.com/watch?v=2cXPjhOhqE0
Rayyan is a collaborative tool assisting with organising and managing a systematic review. Rayyan also has a mobile app for Apple and Android devices. There are both free and paid options available.
Rayyan. (2021, November 22). How to do a systematic review: Rayyan systematic review tutorial [Video]. YouTube. https://www.youtube.com/watch?v=1YWABilWWIg
Abstrackr: For optimizing the step of citation screening for systematic reviews: a free, open-source, web-based application for facilitating citation screening for systematic reviews. The program comprises two components; a web-based annotation tool that allows participants in a review to collaboratively screen citations for relevance, and machine learning technologies that semi-automate this process.
Centre for Evidence Sythesis in Health. (2018, April 19). Introduction to Abstrackr [Video]. YouTube. https://www.youtube.com/watch?v=XxKaJF0dgJ0
The Systematic Review Toolbox is an online catalogue of tools that support various tasks within the systematic review and wider evidence synthesis process.
To locate tools to assist with the screening process, under Advanced search select 'Software' and the tick the option 'Screening'
Before you go through the screening process, you need to remove the duplicates from your search. You can use Covidence to do this but it is advised to use EndNote if you can, as EndNote will give you the option of double checking the duplicates and keeping a record of them: