Allied Health Sciences (Graduate Students)

A literature review is:

• a summary and evaluation of the significant research and/or theory published on a topic
• organized in a way that analyzes, integrates, and shows the relationship between research studies, as well as the way each has contributed to an understanding of the topic
• NOT just an annotated bibliography

The purpose of a literature review is to:

• provide an overview of relevant literature, research, and methodology in an area of study
• explore relationships among the prior research
• evaluate the prior research
• identify gaps and discrepancies in the literature
• identify areas of controversy in the literature
• make an argument for why further study of your research question is important to a field

It helps researchers:

• establish the context and significance of the problem
• discover appropriate subject vocabulary
• discover prominent journals and authors on your topic
• identify methodologies
• identify what has been researched and where gaps may be found—underused methodologies, designs, populations

• focus your research topic

Evidence synthesis refers to a range of methods, including systematic reviews, that researchers use to identify, analyze, and synthesize previous studies that investigate the same question or topic. The aim is to come to an overall understanding of the results of all the evidence available to answer a specific research question. 

A High Quality Systematic Review should seek to 

• Identify all relevant published and unpublished evidence
• Select studies or reports for inclusion
• Assess the quality of each study or report
• Synthesize the findings in an unbiased way 
• Interpret the findings and present a balanced and impartial summary

Undertaking a systematic review:What you need to know by Livinski et al. from NIH's Office of Research Services is a good resource for learning about the detailed steps and requirements of a systematic review.

For more information see The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration. By Liberati A et al.

Before starting a systematic review look at PROSPERO, an International prospective register of systematic reviews hosted by The University of York and the National Institute for Health Research.  Checking this can help researchers avoid duplicating current systematic reviews, saving the researcher a lot time and heartache.  Registering with PROSPERO is free and allows researchers to notify others of their prospective reviews.