Gaps in knowledge and systematic literature reviews

Nathalie Peira works as project manager at the Swedish Agency for Health Technology Assessment and Assessment of Social Services (SBU). In the interview below, she tells us how the work with knowledge gaps and systematic literature reviews can benefit clinical researchers.

Nathalie Peira, SBU

What is a systematic literature review?

A systematic literature review aims to identify, evaluate and synthesise the evidence for a delimited research question. Often it concerns estimating a therapy effect. What makes a literature review systematic is that all steps of the process are pre-defined and well-documented. Some steps, such as the choice of studies, should also be done by two independent persons, in order to safeguard quality.

The process includes:

  • a detailed definition of the research question (the effect of which therapy, on which outcome measurements, for whom, compared to which other therapy)
  • a literature search aimed at finding all relevant studies
  • an audit of the studies, in terms of both relevance (whether the study answers in detail the pre-defined question) and quality
  • a synthesis, if possible in the form of a meta-analysis, to estimate the effect and conclusions
  • - sometimes an evidence grading is also included, aimed at grading how reliable the conclusions are (SBU uses the GRADE system).

How can clinical researchers use knowledge gaps?

Clinical researchers can use SBU’s database of scientific knowledge gaps to find out whether more practice-related research is needed in the area, and what specific questions are lacking studies. You can also see whether a systematic review is needed, to summarise the studies that already exist. The content of the database is continuously updated, but before you start on a study, it is still a good idea to run your own check to see whether anything new has been published. SBU collaborates with research funding bodies to target research funds towards areas with knowledge gaps, but individual researchers can also refer to SBU’s database of scientific knowledge gaps when applying for research funding.

Can clinical researchers carry out a systematic literature review themselves?

A systematic review should preferably be carried out in collaboration between several persons. For one reason, it is difficult to have the right competence by yourself to do all the steps of the process (literature search, subject competence, methodology competence). Also, to follow the process for systematic literature review, at least two persons working independently of each other should also be involved in some steps (assessment of relevance and quality of the studies, and also extraction of data).