Absolute risk reduction
In clinical epidemiology and evidence-based medicine, the absolute risk reduction is a measure that compares the frequency of a clinical outcome in group of patients exposed to a factor compared to a control group of patients. This measure should be contrasted with the relative risk reduction.
|Experimental group||Cell A||Cell B||Total in the experimental group|
|Control group||Cell C||Cell D||Total in the control group|
|Total with the outcome||Total without the outcome|
The confidence intervals can be calculated using the method of Daly:
- Barratt A, Wyer PC, Hatala R, et al (2004). "Tips for learners of evidence-based medicine: 1. Relative risk reduction, absolute risk reduction and number needed to treat". CMAJ 171 (4): 353–8. DOI:10.1503/cmaj.1021197. PMID 15313996. Research Blogging.
- Welch HG et al.Ratio measures in leading medical journals: structured review of accessibility of underlying absolute risks.BMJ. 2006 Dec 16;333(7581):1248. Epub 2006 Oct 23. PMID 17060338
- Daly LE (1998). "Confidence limits made easy: interval estimation using a substitution method.". Am J Epidemiol 147 (8): 783-90. PMID 9554420.