Risk ratio vs odds ratio

In the previous article, we explained that the risk ratio (RR) and the odds ratio (OR) are measures of effect. In this article, we will discuss in more detail the properties of the RR and the OR and how those 2 effect measures are related.

Table I summarizes risks, odds, RRs, and ORs.

Table I
Risks, odds, RRs, and ORs
Event Treatment Control
Yes a b
No c d
Risk a/(a+b) b/(b+d)
Odds a/c b/d
RR [a/(a+c)]/[b/(b+d)]
OR (a/c)/(b/d) = ad∗cb

The risk, or probability, and the odds are related with the following formula:

risk=Odds1+odds
risk = Odds 1 + odds
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Apr 8, 2017 | Posted by in Orthodontics | Comments Off on Risk ratio vs odds ratio
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