Meta-analysis is a structured literature review technique that attempts to combine similar studies to determine the average effect size for a particular treatment under comparable circumstances with comparable participants.
Meta-analysis is all about putting the different pieces of the puzzle together in a scientific way. It combines the findings of many different studies using statistical methods. These studies offer a real, quantifiable sense of where the evidence is leading.
Cumulative evidence is another method used to look at the big picture. Rather than using a complex mathematical model, though, cumulative evidence simply means stacking up all the related studies and figuring out what they say overall.
Think of a fictional detective looking at fingerprints, eyewitness testimony, DNA evidence, and circumstantial evidence, and putting them all together to see what kind of case they build.
|Image courtesy of American Institute of Cancer Research|
Meta-analysis can be used as a guide to answer the question:
'Does what we are doing make a difference to X' even if 'X' has been measured using different instruments across a range of different people?
Meta-analysis provides a systematic overview of quantitative research that has examined a particular question.