Systematic reviews

Systematic reviews occur in different research topics and the purpose may vary. One purpose may, for example, be to map the literature within a subject area, or to produce statistical measures of treatment effects.

• Method
• Formulate and structure a research question
• Create a search query
• Literature search
• Screening tools
• Reference management software
• Documentation

What characterises a systematic review?

Making a systematic review is a time-consuming and resource-intensive job. The issues are very specific and clearly formulated. The information retrieval is performed according to carefully selected criteria based on the purpose of the review. The goal is to find material that is both comprehensive and relevant according to the selected criteria.

• Stick to a strict method
• Use many sources and tools
• Assess and summarise the material you obtain through the searches

There are different types of reviews, such as rapid review, scoping review and systematic review. Some are more comprehensive than others.

What does the workflow look like?

The workflow in a systematic review is often based on the following steps:

• Formulate the research question. To structure the question, there are different models, for example PICO, PEO, SPICE or SPIDER.
• Establish any other inclusion and exclusion criteria, such as applicable publication types, year of publication and study design/method.

• Identify search terms from the research question.
• Find more search terms through, for example, gold standard articles, expert opinions, concept analyses, subject headings, reference lists and citations.

• Do a systematic literature search in the databases you have selected in advance.
• Complete the search with other methods if necessary, for example by manual search in selected journals.

• Clear any duplicates using a screening tool or reference management program.

• Review the studies that emerged in the literature search based on the inclusion and exclusion criteria, relevance and quality. An initial review is often performed by reading abstracts. At the subsequent review, you can then read the full texts of the publications that have been passed on.
• Extract, compile and analyse relevant data from the remaining publications.
• In certain subject areas, an evidence grading is performed where the reliability of the result is assessed. For assessment, for example, the international grading system GRADE can be used.

• Clearly present the entire process in the completed systematic review. It must be possible to follow, evaluate and recreate the work that led to the systematic review.

Useful links