Evidence Synthesis: Systematized Reviews for Students

What is a systematized review?

Systematized reviews occupy a middle ground between narrative literature reviews and systematic reviews. They are more structured and transparent than typical narrative reviews, and this is accomplished by incorporating certain aspects of systematic reviews. However, systematized reviews are not as structured, transparent, or exhaustive as systematic reviews. 

How do you know if you should do a systematized review?

If any of the following items are true, you are likely doing a systematized review. 

• You are doing the review for a class assignment, thesis, capstone, or dissertation.
• You have less than 12 months to complete the review. 
• You are doing the review entirely by yourself or have very limited support from other people. This includes having other people assisting with screening but doing everything else on your own.
• You do not want to create and register a protocol prior to beginning your review.
• You do not want to perform an exhaustive search on your chosen topic in multiple databases. 

The following items are included in full evidence syntheses (systematic or scoping reviews) and are typically included in systematized reviews as well. 

1. Preparation

• Develop a strong research question with a question framework.
• Do preliminary searching to see if anyone has already conducted a review on this topic.
• Create a list of inclusion and exclusion criteria.

2. Protocol

• A formal protocol is not necessary, but creating one will help you structure your project. Documenting your intended steps in a protocol will also be beneficial if you revisit the topic at a later time to create a full evidence synthesis from it. 
• If you create a protocol, you may opt to register it.

3. Searching

• One or more databases are searched; two or three databases typically suffice. Comprehensive searching is not required in a systematized review.
• Grey literature does not need to be included, but you may choose to do so.
• Your search may have a limited publication date range (i.e. anything published in the past 20 years) in order to limit the number of citations to screen.
• Documenting your search process in a transparent and replicable way is a key part of a systematized review. 

4. Citation Management

• You will deduplicate citations manually in a citation manager or in a screening software like Covidence.

5. Screening

• Screening is required and is typically broken into 2 phases: title & abstract screening, and full text screening.
• You may use Covidence or another software for screening.
• If you are screening citations yourself, you will need to change the default setting in Covidence from 2 screeners to 1 screener.
• Prior to beginning the full text screening phase, you will need to retrieve the full text PDFs for all citations that you passed through the title & abstract screening phase.

6. Data Extraction

• Data extraction is required for all references that pass through the full text screening stage.

7. Risk of Bias Assessment (Critical Appraisal)

• Not required, but you may choose to incorporate it.

8. Writing and Reporting

• Search results should be reported in as much detail as possible.
• PRISMA flow diagrams may be used but are not required.
• PRISMA checklists may be used but are not required.

You may opt to include the following aspects in your review, but they are not required for systematized reviews.

• A registered protocol
• More than one person working on the review
• A exhaustive search in multiple databases
• Searching for grey literature
• Risk of bias (quality assessment) is not required but may be included
• A completed PRISMA flowchart

Can a systematized review be published?

Yes, systematized reviews do get published in academic journals. If there is a specific journal you want to publish in, make sure to check its eligibility requirements or contact the journal directly to see if they accept systematized reviews.

Can a systematized review be turned into a full systematic review or scoping review later?

Yes, you can revisit your systematized review at a later date and conduct a full systematic or scoping review on the same topic. Keep in mind that you will need to start at the beginning and progress through each step again.

Why can't a scoping review or systematic review be part of a dissertation?

The methodological requirements of scoping and systematic reviews are often at odds with what is allowable in a dissertation. The biggest issue is having team members; departments often do not allow other people to be involved in a dissertation to the extent that is required for a scoping or systematic review. If your department allows other people to be involved in the work at a co-authorship level (i.e., doing more than just screening), you may be able to incorporate a systematic or scoping review into your dissertation. 

Where can you find more information on systematized reviews?

Currently, there isn't much guidance published on systematized reviews. If you have questions or need additional support, feel free to contact a librarian.