Systematic review guide

This initial stage of screening requires scanning the titles and abstracts of the now de-duplicated final list of records or references to make a decision on eligibility for continued inclusion in the review process.
This stage should not be started until you have completed your final searches in all databases. 

During the title and abstract screening, for each reference, each reviewer should read the title and abstract and decide: 

• No: This reference does not meet one (or more) inclusion criteria
• Yes: This reference appears to meet inclusion criteria
• Maybe: There is not enough information in the title or abstract to make a decision 

Conflicts and maybes can usually be quickly resolved but if not, a third reviewer can be called in to make the final decision. 

In this section we will usually describe what is being screened as “references” rather than “studies” or "reports”. This is because during this step you may discover different publications reporting on the same study. At this stage we are just screening the reference or record of the publication or report of the study, not the study itself. For more information on dealing with multiple reports of the same study see the Cochrane Handbook sections 4.6.1 and 5.6.2.  

• As with many parts of the Systematic review methodology, the screening process is designed to reduce bias and be reported transparently. 

• Ideally, screening should be done by two reviewers, working independently. However at the Ti/Ab level, one person is sometimes considered to be acceptable.

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

• Pilot the screening process. Test your eligibility or inclusion criteria on a sample of around 6-8 references, including ones that are thought to be definitely eligible, definitely not eligible and doubtful. This pilot test should help refine and clarify the eligibility criteria, train the people who will be applying them and ensure that the criteria can be applied consistently by more than one person. 

• Agree on a conflict resolution protocol before screening. 

• Aim to be on the side of over-inclusion, rather than under-inclusion, as there is still another screening step to further weed out unsuitable studies. However, do not fall into the trap of keeping irrelevant references just because they seem interesting.  

• Scan the title and abstract for relevance with your PICO in mind. The first No is reason to discard the reference. Where your population is children and the study in the reference you are screening only includes adults, you can discard without bothering to check the interventions, comparators and outcomes. 

• Ensure your screening process is blinded, meaning other reviewers should be unable to see your “votes” for Yes/No/Maybe until they have cast their own, and vice versa. Covidence has this built into its workflow. 

• Each decision should be recorded so you can report these numbers of included and excluded references as required in the PRISMA flowchart. Covidence does this automatically. However, you do not need to record your reasons for exclusion at this stage.  

• Do not move on to any full-text screening until you have fully completed title and abstract screening, including resolving conflicts.