While all literature reviews can be done in a systematic way, not every literature review is performed according to a method within the 'systematic review' family.
For example, scoping and systematic reviews both aim to be comprehensive, transparent, unbiased, and reproduceable. This is not always the case with the type of narrative literature review you might want to write for the background section of a scholarly article or the introductory chapter of a book.
IMPORTANT! Make sure that your research question and methodology match. In other words, one type of review is not better than another, and your research question may be answered best by a review type other than a systematic review.
|Narrrative literature review||Scoping review||Systematic review|
|Research question||General discussion of topic||Broad overview of topic||Focused (narrow or clinical) question or hypothesis|
|Protocol (a priori)||No||Sometimes||Yes|
|Literature search||Not comprehensive||Comprehensive to locate all relevant studies||Comprehensive to locate all relevant studies|
|Inclusion criteria||Undefined; usually only studies that support claims||Explicit description of study types to be included||Explicit description of study types to be included|
|Standardized data extraction||No||Yes||Yes|
|Critical appraisal (assessment of risk of bias)||No||Sometimes; not required||Yes|
|Number of reviewers||Usually one||Usually two or more||Must be at least two|
Scoping and systematic reviews share many of the same processes since they both use transparent and rigorous methods to comprehensively identify and analyze all the relevant literature to answer a research question. The main difference between the methods depends on what is the aim or purpose of the review.
Scoping reviews aim to:
Systematic reviews aim to:
Adapted from: Pham, M., Rajić, A., Greig, J., Sargeant, J., Papadopoulos, A., & McEwen, S. (2014). A scoping review of scoping reviews: advancing the approach and enhancing the consistency. Research Synthesis Methods, 5(4), 371–385. https://doi.org/10.1002/jrsm.1123
Adapted from: Munn, Z., Peters, M., Stern, C., Tufanaru, C., McArthur, A., & Aromataris, E. (2018). Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Medical Research Methodology, 18(1), 143–143. https://doi.org/10.1186/s12874-018-0611-x
There are many types of reviews, each with slightly different purpose and methodology. For example:
For details and examples of other review types, see the additional resources listed below.