A systematic review consists on combining the results of several studies to answer a research question and not only what has been written on a theme, as is the case of the literature review. In Social Sciences, more often, one seeks to evaluate the effectiveness of an intervention.
Systematic reviews use systematic and explicit methods to identify, select and critically appraise relevant research and to collect and analyse data from the studies included on the review (Glossary of Cochrane). Thus, in order to minimise bias and make reviews reproducible, pre-specified research questions and methods that are documented in protocols are used. Statistical methods (meta-analysis) may or may not be used to analyse and summarise the results of the included studies.
Systematic reviews are used to:
It is common for students or researchers to confuse systematic reviews with literature reviews; however, before beginning the process, it is very important to know the differences between the two because systematic reviews require more time and resources.
| Systematic Review | Litterature Review | |
| Definition | High-level of primary research on a focused question that identifies, selects, synthesises and appraises all high quality research evidence relevant to that question | Qualitatively summarises evidence on a topic using informal or subjective methods to collect and interpret studies |
| Goals | Answers a focused question. Eliminate bias | Provides summary or overview of topic |
| Question |
Clearly defined and answerable question Recommends using PICO as a guide |
Can be a general topic or a specific question |
| Components |
Pre-specified eligibility criteria Systematic search strategy Assessment of the validity of findings Interpretation and presentation of results Reference list |
Introduction Methods Discussion Conclusion Reference list |
| Number of Authors | Three or more | One or more |
| Timeline | Months to years. Average of eighteen months | Weeks to months |
| Requirements |
Thorough knowledge of topic Performs searches of all relevant databases Statistical analysis resources (for meta-analysis) |
Understanding of topic Performs searches of one or more databases |
| Value | Supports evidence-based practice | Provides summary of literature on a topic |
Based on Kysh, Lynn (2013). Difference between a systematic review and a literature review.
