This chapter answers parts from Section A(a) of the old 2011 Primary Syllabus; "Describe the features of evidence-based medicine, including levels of evidence (eg. NH&MRC), meta-analysis and systematic review". It closely resembles the Fellowship exam revision chapter, "Types of studies, their advantages and disadvantages". The specific reference to meta-analysis and systematic review also resembles the sort of stuff that might be expected of a fellowship exam candidate, with the exception of the fact that in the Part II written paper we might be expected to perform a Critical Appraisal of Meta-Analysis Data.
This topic has come up at least twice in the Primary (Question 19 from the second paper of 2010 and Question 8 from the second paper of 2013), and also about five times in the Fellowship Exam, with slightly different expectations from the college. Only slightly. Both Fellowship and Primary candidates have been expected to define meta-analysis and to offer some advantages and disadvantages. Both have at one stage been expected to analyse (or identify the major features) of forest plots and funnel plots. Only Primary candidates have been expected to discuss systematic reviews. Only Fellowship candidates have been expected to delve deeper into the critical appraisal of meta-analysis data to discuss what makes a well-conducted meta-analysis. Thus though material common to Part I and Part II SAQs is duplicated in this chapter, there is a different emphasis when compared to the chapter on Critical Appraisal of Meta-Analysis Data from the Required Reading section for the Fellowship Exam.
As far as definitve resources for this topic go, one cannot go past the excellent review by Bartolucci et al (2010). Unless otherwise stated, this is the primary reference for most of the material which follows.
Meta-analysis is a tool of quantitative systematic review. It is used to weigh the available evidence from RCTs and other studies based on the numbers of patients included, the effect size, and on statistical tests of agreement with other trials.
The definition offered by the CICM Primary examiners can probably be viewed as canonical, and is as follows:
Meta-analysis is process of combining the results of different (randomised) trials to derive a pooled estimate of effect.
The answer from a Part II question (Question 30 from the second paper of 2007) reads slightly differently, "A form of systematic review that uses statistical methods to combine the results from different studies". The Bartolucci paper defines it as "the process of combining the quantitative results of separate (but similar) studies by means of formal statistical methods" Presumably one might get away with using either definition, as they all sound very similar and begin to blend into one another when one reads enough of them.
This SEO-destroying copypasta is from the chapter on Critical Appraisal of Meta-Analysis Data:
The definition offered by the CICM examiners is as follows:
A systematic review is a process of obtaining and evaluating all relevant trials, their statistical analyses and interpretation of results.
How is that different from meta-analysis? Well. An excellent clarification can be found at the website of the Centre for Cognitive Ageing and Cognitive Epidemiology.
A systematic review answers a defined research question by collecting and summarising all empirical evidence that fits pre-specified eligibility criteria.
A meta-analysis is the use of statistical methods to summarise the results of these studies.
Thus, it is possible to have a systematic review which does not include a meta-analysis of trials, but all meta-analysis articles are by this definition systematic reviews. A meta-analysis arises from a systematic review.