Relative risk (RR, relative risk)

the risk, like frequently under a therapy (Verumgruppe, describes e.g. with a test medication) an unwanted event compared with a comparison therapy (control's group, e.g. with Plazebo) arises.

'' RR = [proportional event rate in the Verumgruppe]/[proportional event rate in the control's group] ''

The purchase is always the comparison therapy (control's group) therefore, the RR of the group of comparisons always by definition is 1

'' RR < 1 '' the risk of an unwanted event of the therapy of the Verumgruppe is lower than that the comparison therapy (control's group), the use is larger

'' RR = 1 '' it does not give a difference between the treatment effect of around and control's group

'' RR > 1 '' the risk of an unwanted event of the therapy of the Verumgruppe is higher than that the comparison therapy (control's group), which is therapy of the Verumgruppe with the test medication the comparison therapy (control's group) underlaid.

Example:

By a therapy the number of deaths of 10 (comparison therapy, e.g. with Plazebo) on 4 at a collective of 1000 pro gangs (around therapy) changes. The relative Risiko' under the Verumtherapie amounts to 4/10 = "0.4 = 40%, the RR of the control's group by definition 1. The mortality risk sinks thus in the Verumgruppe clearly. The relative risk reduction (RRR, see below)" amounts to '0.06 = 60%

The absolute risk (ACRE) 'of a death amounts to in contrast to this '0.004 (= 0.4%) in the Verumgruppe and 0.01 (= 1.0%) in the group of comparisons (control's group). The absolute risk reduction (ARR) is the difference, amounts to thus "only" 0.006%.

Relative risk reduction (RRR, English: relative risk reduction)

The relative risk reduction describes, around how much per cent the risk is reduced by an intervention.

'' RRR = RR-1 ''

A change of the mortality of 2% to 1,6% is a change by 20% or 0,4 per cent points.

Computation:

'' Relative risk (RR) '' the Verumtherapie 1.6/2.0 = 0.8 = 80%

'' Relative risk (RR) '' the comparison therapy (control's group) 1 by definition = 100%

RRR of the Verumgruppe' = 0.8-1 = "-0.2" = ''' - 20% ''

This usual type of representation of the use of therapies is supplemented increasingly by other more descriptive statistic sizes, which compute the basic portion: Number of necessary treatments, absolute risk reduction or also increase of the life expectancy; the reason is that also the basic portion of the illness is visible here.

Articles in category "Relative risk reduction"

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• Glossary
  RRR (relative risk reduction). The proportional reduction in rates of bad outcomes between experimental and control participants in a trial, calculated as ...


• Measuring the size of an intervention
  Three commonly used measures of effect size are relative risk reduction (RRR), absolute risk reduction (ARR), and the number needed to treat (NNT) to ...


• Relative Risk Reduction
  The absolute risk of disease is 0.001%. The relative risk is 0.00001/0.001 = 0.1 and the relative risk reduction is 1- 0.1 = .9 or 90% while the absolute ...


• Tips for Learners of Evidence-Based Medicine: Relative Risk Reduction
  Describes how to estimate a treatment's effectiveness and explains the concepts of risk reduction,...