The term "Literature Review" is used to cover many different types of reviews. (See the table at the bottom of this page.) Thus, the first step would be to confirm with your professor what the expectations are for the literature review. Next, one follows a series of steps to methodically conduct the review.
NYU Librarians were able to describe the steps of a PICO-utilizing literature review within a one page table.
Entire books, handbooks and guides are written on how to perform literature reviews. For example:
Note that conducting a Cochrane Systematic Review can take a team of researchers one to two years. Proposing and registering new Cochrane Reviews.
In an age of information abundance, we have to critically discern where we are receiving our information. Here are some helpful guidelines when appraising a source's authority:
AUTHORITY
- How well known is the publisher? Is it from a well known company or government agency, or is it self-published?
- Is the subject well-researched? Check the source for citations. Is their information predicated upon credible sources?
- What is the author's expertise on the subject? Do they have significant knowledge on the topic, such as a relevant degree or a body of previously published and vetted work on the subject?
CURRENCY
- When was this published? Do you believe this resource contributes to the current discussion on the topic?
PURPOSE
- What was the reason for publishing this article? To inform, persuade, to call to action? Can you detect bias or emotion in this resource? Look for objectivity.
When performing a literature review, it's important to have a specific set of guidelines available when determining article relevance to your study. Ask questions that would determine suitability to your research question. These questions are also posed to determine validity of the study. We asked some of the basic questions to filter above for credibility, but let's look at applicability. Some questions to consider:
Does the article attempt to answer the same question as your research question?
Does the paper pose a clear hypothesis?
Is the study design valid to your question?
Is the population surveyed statistically significant?
Are they clear on who was included in the study, who was not, and why?
Are the study's demographics similar or the same as your population of focus?
Does the study share the same outcome?
Are the results and conclusions clearly stated?
There are more questions you may wish to consider. Be sure to read the abstract of each article you are considering. Many questions regarding suitability to your question and validity can be answered through the abstract.
Remember that librarians are information specialists and can help you with creating sophisticated search strings in PubMed or other databases.
Circulation/Reference: 210-619-7038
Reproduced from: Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009 Jun;26(2):91-108. doi:10.1111/j.1471-1842.2009.00848.x Review. PubMed PMID: 19490148. |
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Label |
Description |
Search |
Appraisal |
Synthesis |
Analysis |
|
Critical review |
Aims to demonstrate writer has extensively researched literature and critically evaluated its quality. Goes beyond mere description to include degree of analysis and conceptual innovation. Typically results in hypothesis or model. |
Seeks to identify significant items in the field. |
No formal quality assessment. Attempts to evaluate according to contribution. |
Typically narrative, perhaps conceptual or chronological. |
Significant component: seeks to identify conceptual contribution to embody existing or derive new theory. |
|
Literature review |
Generic term: published materials that provide examination of recent or current literature. Can cover wide range of subjects at various levels of completeness and comprehensiveness. May include research findings. |
May or may not include comprehensive searching. |
May or may not include quality assessment. |
Typically narrative. |
Analysis may be chronological, conceptual, thematic, etc. |
|
Mapping review/systematic map |
Map out and categorize existing literature from which to commission further reviews and/or primary research by identifying gaps in research literature. |
Completeness of searching determined by time/scope constraints. |
No formal quality assessment. |
May be graphical and tabular. |
Characterizes quantity and quality of literature, perhaps by study design and other key features. May identify need for primary or secondary research. |
|
Meta-analysis |
Technique that statistically combines the results of quantitative studies to provide a more precise effect of the results. |
Aims for exhaustive searching. May use funnel plot to assess completeness. |
Quality assessment may determine inclusion/exclusion and/or sensitivity analyses. |
Graphical and tabular with narrative commentary. |
Numerical analysis of measures of effect assuming absence of heterogeneity. |
|
Mixed studies review/mixed methods review |
Refers to any combination of methods where one significant component is a literature review (usually systematic). Within a review context it refers to a combination of review approaches for example combining quantitative with qualitative research or outcome with process studies. |
Requires either very sensitive search to retrieve all studies or separately conceived quantitative and qualitative strategies. |
Requires either a generic appraisal instrument or separate appraisal processes with corresponding checklists. |
Typically both components will be presented as narrative and in tables. May also employ graphical means of integrating quantitative and qualitative studies. |
Analysis may characterize both literatures and look for correlations between characteristics or use gap analysis to identify aspects absent in one literature but missing in the other. |
|
Overview |
Generic term: summary of the [medical] literature that attempts to survey the literature and describe its characteristics. |
May or may not include comprehensive searching (depends whether systematic overview or not). |
May or may not include quality assessment (depends whether systematic overview or not). |
Synthesis depends on whether systematic or not. Typically narrative but may include tabular features. |
Analysis may be chronological, conceptual, thematic, etc. |
|
Qualitative systematic review/qualitative evidence synthesis |
Method for integrating or comparing the findings from qualitative studies. It looks for ‘themes’ or ‘constructs’ that lie in or across individual qualitative studies. |
May employ selective or purposive sampling. |
Quality assessment typically used to mediate messages not for inclusion/exclusion. |
Qualitative, narrative synthesis. |
Thematic analysis, may include conceptual models. |
|
Rapid review |
Assessment of what is already known about a policy or practice issue, by using systematic review methods to search and critically appraise existing research. |
Completeness of searching determined by time constraints. |
Time-limited formal quality assessment. |
Typically narrative and tabular. |
Quantities of literature and overall quality/direction of effect of literature. |
|
Scoping review |
Preliminary assessment of potential size and scope of available research literature. Aims to identify nature and extent of research evidence (usually including ongoing research). |
Completeness of searching determined by time/scope constraints. May include research in progress. |
No formal quality assessment. |
Typically tabular with some narrative commentary. |
Characterizes quantity and quality of literature, perhaps by study design and other key features. Attempts to specify a viable review. |
|
State-of-the-art review |
Tend to address more current matters in contrast to other combined retrospective and current approaches. May offer new perspectives on issue or point out area for further research. |
Aims for comprehensive searching of current literature. |
No formal quality assessment. |
Typically narrative, may have tabular accompaniment. |
Current state of knowledge and priorities for future investigation and research. |
|
Systematic review |
Seeks to systematically search for, appraise and synthesize research evidence, often adhering to guidelines on the conduct of a review. |
Aims for exhaustive, comprehensive searching. |
Quality assessment may determine inclusion/exclusion. |
Typically narrative with tabular accompaniment. |
What is known; recommendations for practice. What remains unknown; uncertainty around findings, recommendations for future research. |
|
Systematic search and review |
Combines strengths of critical review with a comprehensive search process. Typically addresses broad questions to produce ‘best evidence synthesis’. |
Aims for exhaustive, comprehensive searching. |
May or may not include quality assessment. |
Minimal narrative, tabular summary of studies. |
What is known; recommendations for practice. Limitations. |
|
Systematized review |
Attempt to include elements of systematic review process while stopping short of systematic review. Typically conducted as postgraduate student assignment. |
May or may not include comprehensive searching. |
May or may not include quality assessment. |
Typically narrative with tabular accompaniment. |
What is known; uncertainty around findings; limitations of methodology. |
|
Umbrella review |
Specifically refers to review compiling evidence from multiple reviews into one accessible and usable document. Focuses on broad condition or problem for which there are competing interventions and highlights reviews that address these interventions and their results. |
Identification of component reviews, but no search for primary studies. |
Quality assessment of studies within component reviews and/or of reviews themselves. |
Graphical and tabular with narrative commentary. |
What is known; recommendations for practice. What remains unknown; recommendations for future research. |
