Table of Contents

## What is the difference between Kaplan Meier and Cox hazard regression?

Kaplan–Meier provides a method for estimating the survival curve, the log rank test provides a statistical comparison of two groups, and Cox’s proportional hazards model allows additional covariates to be included. Both of the latter two methods assume that the hazard ratio comparing two groups is constant over time.

## What is the Logrank test when is it used and what is the benefit its use involves?

The logrank test, or log-rank test, is a hypothesis test to compare the survival distributions of two samples. It is a nonparametric test and appropriate to use when the data are right skewed and censored (technically, the censoring must be non-informative).

## What is Gehan Breslow test?

The Gehan-Breslow-Wilcoxon test does not require a consistent hazard ratio, but does require that one group consistently have a higher risk than the other. If the two survival curves cross, then one group has a higher risk at early time points and the other group has a higher risk at late time points.

## What is Cox regression used for?

The Cox proportional-hazards model (Cox, 1972) is essentially a regression model commonly used statistical in medical research for investigating the association between the survival time of patients and one or more predictor variables.

## What are the assumptions of Cox proportional hazards model?

The Cox proportional hazards model makes two assumptions: (1) survival curves for different strata must have hazard functions that are proportional over the time t and (2) the relationship between the log hazard and each covariate is linear, which can be verified with residual plots.

## Is Cox regression logistic?

Cox proportional hazard risk model is a method of time-to-event analysis while logistic regression model do not include time variable. The logistic regression result can be presented in addition to the Cox model, e.g. to better visualize the differences in the number of events between groups.

## Why is it called log rank test?

The null hypothesis for the test is that that there is no difference in the survival experience of the subjects in the different groups being compared. Its name derives from its relation to a test that uses the logarithms of the ranks of the data.

## What is Logrank P?

The logrank test is used to test the null hypothesis that there is no difference between the populations in the probability of an event (here a death) at any time point. The analysis is based on the times of events (here deaths).

## What is the Breslow Day Test?

A test for homogeneity of odds ratio, which is used to evaluate changes in the degree of difference between 2 datasets being analysed in 2 different periods.

## How do you interpret a Cox regression?

The coefficients in a Cox regression relate to hazard; a positive coefficient indicates a worse prognosis and a negative coefficient indicates a protective effect of the variable with which it is associated.

## What is the difference between logistic regression and Cox regression?

Cox proportional hazard risk model is a method of time-to-event analysis while logistic regression model do not include time variable. In such a situation, logistic regression will not reveal the benefits of the intervention in the study, while the Cox model does.

## What is the Mantel-Haenszel Chi-square test?

Mantel-Haenszel Chi-Square Test The Mantel-Haenszel chi-square statistic tests the alternative hypothesis that there is a linear association between the row variable and the column variable. Both variables must lie on an ordinal scale.

## What is the purpose of the Mantel-Cox test?

It is widely used in clinical trials to establish the efficacy of a new treatment in comparison with a control treatment when the measurement is the time to event (such as the time from initial treatment to a heart attack). The test is sometimes called the Mantel–Cox test, named after Nathan Mantel and David Cox.

## What is the null hypothesis of the Cochran–Mantel–Haenszel Chi-square test?

It is also known as the Mantel–Cox test and can be regarded as a time-stratified version of the Cochran–Mantel–Haenszel Chi-square test. The null hypothesis for the test is that that there is no difference in the survival experience of the subjects in the different groups being compared.

## What is the Cochran-Mantel-Haenszel test?

In statistics, the Cochran–Mantel–Haenszel test (CMH) is a test used in the analysis of stratified or matched categorical data. It allows an investigator to test the association between a binary predictor or treatment and a binary outcome such as case or control status while taking into account the stratification.