Absolute risk

Absolute risk (or AR) is the probability or chance of an event. It is usually used for the number of events (such as a disease) that occurred in a group, divided by the number of people in that group.{{cite book|editor-last1=Porta|editor-first1=Miquel|title=A dictionary of epidemiology.|date=2014|publisher=Oxford University Press|location=Oxford|isbn=9780199976720|edition=Six|url=http://irea.ir/files/site1/pages/dictionary.pdf|accessdate=11 November 2017}}

Absolute risk is one of the most understandable ways of communicating health risks to the general public.{{cite journal |last1=Trevena |first1=LJ |last2=Davey |first2=HM |last3=Barratt |first3=A |last4=Butow |first4=P |author-link4=Phyllis Butow |last5=Caldwell |first5=P |date=February 2006 |title=A systematic review on communicating with patients about evidence. |journal=Journal of Evaluation in Clinical Practice |volume=12 |issue=1 |pages=13–23 |doi=10.1111/j.1365-2753.2005.00596.x |pmid=16422776 |doi-access=free}}

In difference to absolute risk, the relative risk (RR) is the ratio of the probability of an outcome (probability) in an exposed group to the probability of an outcome in an unexposed group.