Non-inferiority testing for risk ratio, odds ratio and number needed to treat in three-arm trial

Relative Risk, Odds Ratio, Attributable Risk and Number Needed to Treat

The research may or may not be epidemiological but there is a high likelihood that it would use the epidemiological indices discussed in this note. Rate, risk, hazard, incidence, and prevalence are everyday indices of disease occurrence that are used in a large number of research endeavours. Although these indices apparently look simple but many researchers are not fully comfortable in their us...

Odds Ratio, Hazard Ratio and Relative Risk

Odds ratio (OR) is a statistic commonly encountered in professional or scientific medical literature. Most readers perceive it as relative risk (RR), although most of them do not know why that would be true. But since such perception is mostly correct, there is nothing (or almost nothing) wrong with that. It is nevertheless useful to be reminded now and then what is the relation between the rel...

Number Needed to Treat

Deriving number-needed-to-treat and number-needed-to-harm from the SAINT I trial results.

Deriving Number-Needed-to-Treat and Number-Needed-to-Harm From the Saint I Trial Results To the Editor: In their recent publication regarding interpretation of the Stroke-Acute Ischemic NXY Treatment (SAINT I) trial,1 Koziol and Feng use the definition, but not the derivation method, for number-needed-to-treat (NNT) and number-needed-to-harm (NNH) that was previously described.2 As a result the...

Statistical notes for clinical researchers: Risk difference, risk ratio, and odds ratio

72 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Statistical notes for clinical researchers: Risk difference, risk ratio, and odds ratio ...