W4B. Systematic Literature Review, PRISMA Protocol, SLR Structure

Author

Georgy Gelvanovsky

Published

March 19, 2026

1. Summary

1.1 From Literature Review to Systematic Literature Review

A systematic literature review (SLR) is a specific, rigorous form of literature review. The defining characteristic of an SLR is that it uses explicit, pre-defined, systematic methods to collect, screen, and synthesize findings from studies addressing a clearly formulated research question.

Compare this to a conventional (narrative) literature review, where the author selects sources based on their own judgment and familiarity with the field. In a narrative review, the selection process is not fully documented and cannot be reproduced by another researcher. This makes it vulnerable to selection bias—unconsciously favoring sources that confirm existing assumptions.

An SLR addresses these weaknesses:

  • Less biased: The systematic approach, using Boolean searches and predefined criteria, reduces the likelihood that the reviewer will unconsciously select only papers that support a preferred conclusion.
  • More comprehensive: By searching databases exhaustively using structured strings, an SLR captures all relevant literature, not just what the reviewer already knew about.
  • Replicable: Every step is documented. Another researcher can follow the same procedure and arrive at a comparable set of sources.
1.2 The PRISMA Protocol

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is an internationally recognized standard for conducting and reporting systematic reviews. It provides a checklist of items that a well-reported SLR must include and a flow diagram for documenting the screening process.

A simplified version of the PRISMA approach—appropriate for a student-level SLR—involves the following steps:

  1. Define the research question or objective clearly: The RQ should be specific, focused, and answerable through a literature search.
  2. Design a systematic search: Choose databases and construct Boolean search strings.
  3. Screen results using inclusion/exclusion criteria: Apply consistent, pre-defined rules to decide which papers to keep.
  4. Extract data from selected studies: Record key information from each included paper (findings, methodology, limitations).
  5. Synthesize findings and draw conclusions: Combine the extracted data to answer the RQ.
1.3 The IMRaD Structure of an SLR

A systematic literature review is written following the IMRaD structure—the same framework used for empirical research papers:

  • Title: Clearly describes the topic and scope of the review.
  • Introduction: Provides background on the topic, identifies the research gap, and states the RQ or goal.
  • Method: Documents the search strategy, databases used, Boolean string(s), inclusion/exclusion criteria, and screening procedure.
  • Results: Presents the synthesized findings of the included studies, organized to answer the RQ.
  • Discussion: Interprets the results, compares them to other reviews, acknowledges limitations, and suggests implications and future research directions.
  • References: A complete list of all cited works in IEEE format.

This structure is not arbitrary—it mirrors the scientific process itself, moving from question to method to findings to interpretation.

1.4 Identifying the Research Gap for Your SLR

Before finalizing your research question, you must verify that the gap you identified in Step 1 is real and not already covered by existing systematic reviews. To do this:

  1. Retrieve the list of SLRs that cover your topic (found during your initial search).
  2. Identify whether each existing review is systematic: Look for explicit documentation of search strings, databases, and criteria. If these are missing, the review is probably narrative, not systematic.
  3. Compare existing SLRs against your planned review using these parameters:
    • Years of research covered (your review might cover a more recent period)
    • Databases used (you might search databases the existing reviews missed)
    • Features of the topic discussed (you might focus on a specific aspect not previously reviewed)
  4. Articulate your gap explicitly: “Existing systematic reviews on X cover the period up to 2020, but do not address Y. This review fills that gap by…”
1.5 Translating the Gap into a Research Goal

Once you have a clearly articulated gap, converting it into a research question or goal is a matter of phrasing. The gap describes what is missing; the RQ/Goal describes what your review will do about it.

Gap: “No existing systematic review examines the effect of augmented reality on patient education in oncology settings.”

Goal: “This study systematically reviews the literature on the effects of augmented reality on patient education outcomes in oncology.”

The goal is the gap reframed as a positive research intention. It should be concise, specific, and directly derivable from the gap statement.