Regular literature reviews are simply summaries of the literature on a particular topic. A systematic review, however, is a comprehensive literature review conducted to answer a specific research question. Authors of a systematic review aim to find, code, appraise, and synthesize all of the previous research on their question in an unbiased and well-documented manner. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) outline the minimum amount of information that needs to be reported at the conclusion of a systematic review project.
Other types of what are known as "evidence syntheses," such as scoping, rapid, and integrative reviews, have varying methodologies. While systematic reviews originated with and continue to be a popular publication type in medicine and other health sciences fields, more and more researchers in other disciplines are choosing to conduct evidence syntheses.
For help with systematic reviews and other major literature review projects, please send us an email (firstname.lastname@example.org).
These types of studies employ a systematic method to analyze and synthesize the results of numerous studies. "Systematic" in this case means following a strict set of steps - as outlined by entities like PRISMA and the Institute of Medicine - so as to make the review more reproducible and less biased. Consistent, thorough documentation is also key. Reviews of this type are not meant to be conducted by an individual but rather a (small) team of researchers. Systematic reviews are widely used in the health sciences, often to find a generalized conclusion from multiple evidence-based studies.
A systematic method that uses statistics to analyze the data from numerous studies. The researchers combine the data from studies with similar data types and analyze them as a single, expanded dataset. Meta-analyses are a type of systematic review.
A scoping review employs the systematic review methodology to explore a broader topic or question rather than a specific and answerable one, as is generally the case with a systematic review. Authors of these types of reviews seek to collect and categorize the existing literature so as to identify any gaps.
Rapid reviews are systematic reviews conducted under a time constraint. Researchers make use of workarounds to complete the review quickly (e.g., only looking at English-language publications), which can lead to a less thorough and more biased review.
A traditional literature review that summarizes and synthesizes the findings of numerous original research articles. The purpose and scope of narrative literature reviews vary widely and do not follow a set protocol. Most literature reviews are narrative reviews.
Umbrella reviews are, essentially, systematic reviews of systematic reviews. These compile evidence from multiple review studies into one usable document.
Organization such as the Institute of Medicine recommend that you consult a librarian when conducting a systematic review. Librarians at the University of Nevada, Reno can help you:
For help with systematic reviews and other evidence syntheses, please send us an email (email@example.com).
Systematic reviews require specific, focused, and well-formulated research questions. In the health sciences, researchers often use the PICO format to generate research questions. PICO stands for:
It's okay if your question does not fit neatly into the PICO format. (Many lines of inquiry may not have a definable C, for instance.) However, you might find that you'd be better served by another framework, especially if you are investigating a social sciences topic or focusing on certain types of qualitative or policy-based research. For example, another well-known option is the SPIDER (sample, phenomenon of interest, design, evaluation, research type) framework.
A protocol is essentially an "intent to pursue." It's a document outlining the what and how of your proposed systematic review. According to PRISMA, a protocol "describes the rationale, hypothesis, and planned methods of the review. It should be prepared before a review is started and used as a guide to carry out the review."
Your protocol should be made publicly available and registered in a registry. PROSPERO is the registry of choice for the health sciences. The Open Science Framework (OSF) is a good option for those conducting non-clinical systematic reviews.