Does the Logrank test assume proportional hazards?
One thing to note is that the log rank test does not assume proportional hazards per se. It is a valid test of the null hypothesis of equality of the survival functions without any assumptions (save assumptions regarding censoring).
What is the null hypothesis for log-rank test?
The null hypothesis tested by the log-rank test is that of equal event time distributions among groups. Equality of the distributions of event times implies similar event rates among groups not only for the clinical trial as a whole, but also for any arbitrary time point during the trial.
What are the assumptions of the logrank test?
The logrank test is based on the same assumptions as the Kaplan Meier survival curve 3 —namely, that censoring is unrelated to prognosis, the survival probabilities are the same for subjects recruited early and late in the study, and the events happened at the times specified.
What is the purpose of the stat331 logrank test?
STAT331 Logrank Test Introduction: The logrank test is the most commonly-used statistical test for comparing the survival distributions of two or more groups (such as dif- ferent treatment groups in a clinical trial). The purpose of this unit is to introduce the logrank test from a heuristic perspective and to discuss popu- lar extensions.
Is the logrank test based on the Kaplan Meier survival curve?
The logrank test is based on the same assumptions as the Kaplan Meier survival curve—namely, that censoring is unrelated to prognosis, the survival probabilities are the same for subjects recruited early and late in the study, and the events happened at the times specified.
How is the logrank test used in the BMJ?
The analysis is based on the times of events (here deaths). For each such time we calculate the observed number of deaths in each group and the number expected if there were in reality no difference between the groups.