If you are new to the world of systematic reviews, you may find it useful context to understand how they originated as a research method, why they are conducted, and how their production has grown since they were originally proposed. Systematic reviews have their origins in randomized controlled trials and have overtaken them in number in recent years.
Dr. Archie Cochrane, CBE is considered one of the founders of Clinical Epidemiology and the Evidence-based Practice movement. In his 1972 book, Effectiveness and Efficiency: Random Reflections on Health Services, (Cochrane AL. Effectiveness and Efficiency: Random Reflections on Health Services. London: Nuffield Provincial Hospitals Trust; 1972.) he advocated for the use of Randomized Controlled Trials to improve the quality of medical practice.
Image of Dr. Archie Cochrane from Cardiff University Library, Cochrane Archive, University Hospital Llandough and Archie Cochrane: the name behind Cochrane.
In 1979, MEDLINE added over 282,000 records, of which 1,786 were clinical trials. Cochrane was concerned that practitioners were being overwhelmed by the increasing number of RCTs being published and of the growing lack of consistency between their recommendations. That year he wrote the following statement:
“It is surely a great criticism of our profession that we have not organised a critical summary, by speciality and subspeciality, adapted periodically, of all randomised controlled trials”.
Cochrane AL (1979). 1931-1971: a critical review, with particular reference to the medical profession. In: Teeling-Smith G, ed. Medicines for the Year 2000. London: Office of Health Economics, pp 1-11.
With this statement, Cochrane is advocating for the creation of a new publication type that we know today as the systematic review. With the creation of the Cochrane Collaboration in 1993, The status of Systematic Reviews as a cornerstone of the Evidence-based Practice process was firmly established.
| Year | "Randomized Controlled Trial" [Publication Type] OR "Controlled Clinical Trial" [Publication Type] | "Systematic Review" [Publication Type] OR "Meta-Analysis" [Publication Type] |
|---|---|---|
| 2000 | 13,648 | 2,161 |
| 2001 | 1,858 | |
| 2002 | 14,468 | 2,041 |
| 2003 | 16,168 | 2,314 |
| 2004 | 18,321 | 2,818 |
| 2005 | 19,351 | 3,380 |
| 2006 | 19,992 | 4,155 |
| 2007 | 21,318 | 5,163 |
| 2008 | 21,885 | 5,590 |
| 2009 | 22,737 | 6,714 |
| 2010 | 24,487 | 8,148 |
| 2011 | 27,409 | 10,251 |
| 2012 | 29,813 | 12,983 |
| 2013 | 32,075 | 15,910 |
| 2014 | 31,985 | 18,530 |
| 2015 | 31,363 | 20,521 |
| 2016 | 29,995 | 22,112 |
| 2017 | 29,551 | 24,172 |
| 2018 | 28,094 | 26,218 |
| 2019 | 27,992 | 30,178 |
| 2020 | 29,756 | 36,647 |
| 2021 | 30,474 | 43,339 |
| 2022 | 29,382 | |
| 2023 | 23,871 | 37,611 |
Note: Data as of December 2023. Results returned by linked PubMed searches may vary from numbers shown here due to changes made to the database to remove records that are duplicate or out-of-scope.