A list containing the observed number of deaths, the expected number of deaths, the Log-Rank statistic and its p-value
Arguments
futime
follow-up time of the subjects in days
status
0 if censored or 1 if dead at futime
age
age in days
sex
"male" or "female"
entry_date
entry date in the study
ratetable
a table of event rates, such as survexp.fr or survexp.us
Author
Hugo Varet
Details
The Log-Rank is calculated as:
$$LR = (O-E)^2/E$$
where \(O\) is the observed number of deaths and \(E\) is the expected number based on the patients' characteristics (sex, age and entry date in the study).
It follows a Khi-2 distribution with one degree of freedom, which allows to compute its p-value.
References
R. Peto and J. Peto, Asymptotically Efficient Rank Invariant Test Procedures, Journal of the Royal Statistical Society, 1972