Systematic reviews: Type of reviews

• Narrative reviews
  A status article, where the author expresses his or her personal opinion. It is a critique, arugument or summary of selected articles and books on a given topic. 
  Because of the large degree og subjectivity, a narrative review is considered a low evidence paper.
• Systematisk review
  A predefined topic, where inclusion and exclusion criteria are determined a priori. 
  A SR has a strict structure that follows a review guide, e.g. PRISMA
  Contatins a qualitative analysis and evaluation of bias. 
  Must include a transparent and reproducible systeamtic search 
• Meta-analysis
  A statistical technique for combining data from multiple studies identified in a systematic review. It tries to provide a precise estimate of the effect of the measure under analysis on a particular outcome using data from all relevant studies of adequate quality. 
• Cochrane reviews
  A Cochrane Review is a systematic review of research in health care and health policy that is published in the Cochrane Database of Systematic Reviews
• Rapid Reviews are written with a short deadline and aim to inform decisions regarding policy, updates of previews reviews and other timely research topics. A rapid review speeds up the systematic review process by omitting stages of the systematic review, making it less rigorous. 
• Living systematic reviews. 
  Living systematic review (LSR) is continually updated, incorporating relevant new evidence as it becomes available.
  See more here: Living systematic review

Systematic reviews are not common practice in the Humanities and Legal dogmatic field. Preferred approaches include: 

• Systematic literature searches (the same methodological approach as SR) within a specific field using a structured, systematic and transparent approach or (as in narrative reviews) searches scoping the current state of knowledge on a topic or discipline. Typically, the search is based on a need to develop new perspectives or understandings through the literature. Both search methods provide the foundation for articles, books, etc. 
• Systematiske reviews, Research literature reviews, Scoping reviews and Narrative reviews occur in forensic sociology and criminology, and also in some disciplines in the Humanities such as Media Studies, Philosophy, Rheotic, Library and Information Science, Linguistics and language technology including Audiologopedics.

Types of reviews
There are many different types of reviews, and systeamtic reviews are just one of them. Read the short descriptions below, and find referendes to relevant literature on the subject of review types. 

Research literature reviews
Overall term describing reviews that use the systematic and transparent approach advocated in systematic reviews. You conduct a comprehensive search of all available literature on a topic or problem area in a structured and systematic way, but do not necessarily apply review protocols, standards for the search, search protocols and reporting standards. The purpose is to map what has been written on a subject or problem. research literature reviews can be similar to scoping reviews. 

Systematiske reviews
The literature search aims to identify everything that has been written on a problem area/clinical question (including grey literature) and avoid or reduce as much as possible bias in the evidence/literature. There are establihed protocols and standards for designing and conducting the search, how to evaluate the quality of the identified literature/evidence (critical appraisal) and how to structure the review and report the findings, e.g. PRISMA. 

Scoping reviews
Often the prepatory work to a systematic review, in that you map the existing literature within a topic - how much is written, how the topic is written about, where there are gaps in the literature and identify the need for revision and updates. In other words, a scoping review sets the context for a given research area. Typically a scoping review covers a wide subject area and includes many different types of studies. 

Meta-analysis
Meta-analysis use statistical techniques to combine data from the examined individual research studies identified in a systematic review, and use the pooled data to come to new statistical conclusions.The validity of the meta-analysis depends on the comparibility of the data from the disparate studies produces.

Traditional narrative reviews
In a narrative review, the author subjectively reviews a selection of literature to illustrate a problem of interest. The purpose is to present  their expert opinion on ”the current state of knowledge” on a topic or problem, and also to provoke new perspecives or understanding. 

All the aforementioned review types are used in psychology:

• In medical psychology, e.g. clinical psychology and cognitive psychology the conditions described under "Types of reviews in Health Sciences" apply, where as in the more humanistic psychologies narrative and literature reviews are more common. 

In Social Sciences, systematic reviews are not yet common practice. Examples are found across many subjects, such as criminality, education, social welfare, transport and health.  The usefuleness of a SR is being investigated in polical science, where SR give stakeholders and decision-makers the possibility to: 

• get an overview of the effectiveness of different political innovations. 
• identify gaps in research or new connections to be explored.

As of yet, SR are not used to their full potential in political science. There is some disagreement on the suitability of the method (read more in the recommended readings on the "Literature" page of this website).