Evidence-Based Medicine & Statistics

Relative Risk RR

TRGöreceli Risk
Also known as:Risk ratio

The ratio of the risk (cumulative incidence) of an outcome in an exposed or treated group to the risk in an unexposed or control group over the same period.

Formula

RR = [a / (a + b)] / [c / (c + d)] RR = EER / CER

In depth

RR = 1 indicates no difference, RR < 1 a lower risk and RR > 1 a higher risk in the exposed or treated group. It can be calculated directly from cohort studies and trials but not from case–control studies, where the odds ratio is used instead.

In a 2 × 2 table, a and b are exposed people with and without the outcome, and c and d unexposed people with and without it; in trials the same ratio is the experimental event rate (EER) divided by the control event rate (CER). For example, event rates of 6% on treatment and 10% on control give RR = 0.6.

Clinical pearl

A relative risk alone can exaggerate the importance of an effect when baseline risk is low; the absolute risks from which it was derived should always be considered.

TRIn Turkish

Göreceli Risk

Belirli bir süre içinde maruz kalan ya da tedavi edilen gruptaki bir sonlanım riskinin (kümülatif insidansın), maruz kalmayan ya da kontrol grubundaki riske oranıdır.

RR = 1 fark olmadığını, RR < 1 maruz kalan ya da tedavi edilen grupta daha düşük, RR > 1 ise daha yüksek riski gösterir. Kohort çalışmalarından ve klinik çalışmalardan doğrudan hesaplanabilir, ancak olgu–kontrol çalışmalarından hesaplanamaz; bu çalışmalarda odds oranı kullanılır.

2 × 2 tabloda a ve b sonlanımı olan ve olmayan maruz kişileri, c ve d ise sonlanımı olan ve olmayan maruz kalmamış kişileri gösterir; klinik çalışmalarda aynı oran deney grubu olay oranının (EER) kontrol grubu olay oranına (CER) bölümüdür. Örneğin tedavi grubunda %6, kontrol grubunda %10 olay oranı RR = 0,6 verir.

Başlangıç riski düşük olduğunda göreceli risk tek başına etkinin önemini abartabilir; hesaplandığı mutlak riskler her zaman göz önünde bulundurulmalıdır.

Diğer adları:Göreli risk · Rölatif risk · Risk oranı
Updated 24.09.2026 1 views Educational reference — verify against current sources before clinical use.

Read next

Odds RatioOdds Oranı

The ratio of the odds of an outcome (or exposure) in one group to the odds in another group, where the odds is the probability that an event occurs divided by the probability that it does not.

 Absolute Risk ReductionMutlak Risk Azalması

The arithmetic difference between the event rate in the control group and the event rate in the treated group, expressing the absolute benefit of a treatment over a defined period.

 Relative Risk ReductionGöreceli Risk Azalması

The proportional reduction in the risk of an outcome in a treated group compared with a control group, calculated as the absolute risk reduction divided by the control event rate.

 Hazard RatioHazard Oranı

The ratio of the hazard (instantaneous event rate) in one group to that in another, usually estimated from time-to-event data with a Cox proportional hazards model.

 Confidence IntervalGüven Aralığı

A range of values, calculated from sample data, that is expected to contain the true population value of an estimate with a stated level of confidence, conventionally 95%.

 Cohort StudyKohort Çalışması

An observational study that follows groups of people defined by their exposure (e.g., to a drug) over time and compares the incidence of outcomes between exposed and unexposed groups.