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A literature review gives you a fast, structured account of what has already been published on a topic, and its main weakness is that the way studies are chosen is often not explicit enough for a reader to check. This guide attributes each advantage and disadvantage to a named source, the 2009 typology of review types by Grant and Booth, instead of repeating unsourced lists, and then show which weaknesses disappear when you switch to a different kind of review.
What a literature review is
A literature review is a written examination of published material on a subject. Grant and Booth, in their analysis of 14 review types, describe it through the MeSH scope note: “Published materials which provide an examination of recent or current literature.” It generally involves some process for identifying materials, “whether or not requiring a formal literature search” (Grant and Booth, 2009; see Sources).
That last phrase is the key to everything below. A literature review does not promise an exhaustive search, a formal quality appraisal or a pre-specified protocol. Those are features of other review types, such as the systematic review. The two are often confused; the comparison narrative review vs systematic review sets out the difference in detail.
Advantages of a literature review
It consolidates what is already known
Grant and Booth list the perceived strength of the method as seeking “to identify what has been accomplished previously, allowing for consolidation, for building on previous work, for summation, for avoiding duplication and for identifying omissions or gaps.” Each of those is a practical benefit:
- Consolidation and summation: scattered findings are brought into one account a reader can follow.
- Building on previous work: a new study or proposal can start from the established position instead of from zero.
- Avoiding duplication: you can see whether the question you plan to ask has already been answered.
- Identifying omissions or gaps: the gaps you find become the justification for new research.
It does not require a fixed protocol
Because the method does not demand a prescribed search or appraisal procedure, an author can work with the material that is most relevant to the argument. In Grant and Booth’s Table 1, the literature review’s search “may or may not” be comprehensive and quality assessment “may or may not” be included. That flexibility is why the format suits introductions, background sections and orienting overviews.
Disadvantages of a literature review
No explicit intent to maximize scope or analyse data
Grant and Booth note that “literature reviews lack an explicit intent to maximize scope or analyse data collected.” A reader therefore cannot assume that all relevant studies were found.
Open to bias in what is included
The same authors state that conclusions are “open to bias from the potential to omit, perhaps inadvertently, significant sections of the literature or by not questioning the validity of statements made.” They add that “authors may only select literature that supports their world view.” Selection bias of this kind is invisible unless the author documents how sources were found, which is why the next section matters.
Blurred boundaries between review types
Grant and Booth conclude that “only a handful of review types possess prescribed and explicit methodologies and many of the labels used fall short of being mutually exclusive.” In practice, two papers both called “literature reviews” can differ widely in rigour, so the label alone tells a reader little about how much weight to give the conclusions.
How to reduce the weaknesses
The following steps follow directly from the weaknesses above. They are practical consequences of the cited limitations, not requirements from a standard.
- Record how you searched. Name the databases, the search terms and the dates, so the selection can be checked.
- State your inclusion and exclusion criteria before you read, and apply them consistently.
- Say plainly that the search was not exhaustive if it was not, instead of implying completeness.
- Look for evidence against your position and report it, to counter the tendency to select literature that supports a world view.
- Question the validity of claims you cite instead of repeating them because they are widely quoted. Selective reporting of positive findings is discussed under publication bias.
When to choose another review type
If a disadvantage above is a deal-breaker for your purpose, a different review type may fit better. The table uses only what the cited sources state.
| Review type | What the source says |
|---|---|
| Literature review | Search may or may not be comprehensive; quality assessment may or may not be included (Grant and Booth, Table 1) |
| Critical review | No formal quality assessment, but goes beyond description to analysis and conceptual innovation (Grant and Booth) |
| Scoping review | PRISMA publishes an extension for scoping reviews (PRISMA website) |
| Systematic review | PRISMA is a guideline designed to improve the reporting of systematic reviews (PRISMA website) |
For the reporting side, see the guide to PRISMA and systematic review methodology. PRISMA 2020 primarily provides guidance for reporting systematic reviews that evaluate the effects of interventions; extensions exist for other synthesis types.
FAQ
Is a literature review the same as a systematic review?
No. A literature review examines published material and may or may not use a formal search. A systematic review is a distinct review type with explicit methods, and PRISMA is the guideline designed to improve how such reviews are reported.
Is a literature review biased?
It can be. Grant and Booth identify the risk of omitting significant parts of the literature, perhaps inadvertently, and of authors selecting only literature that supports their world view. Documenting the search and reporting contrary evidence reduces the risk but does not remove it.
What is the main advantage of a literature review?
It consolidates previous work, helps avoid duplication and identifies omissions or gaps that justify new research.
What is the main disadvantage of a literature review?
It lacks an explicit intent to maximize scope or analyse data, so its conclusions depend heavily on which sources the author happened to include.
Sources
- Grant MJ, Booth A. “A typology of reviews: an analysis of 14 review types and associated methodologies.” Health Information and Libraries Journal 2009;26(2):91-108. DOI: https://doi.org/10.1111/j.1471-1842.2009.00848.x. Checked 2026-10-29.
- PRISMA statement, https://www.prisma-statement.org/. Checked 2026-10-29.
