cox.zph {survival} | R Documentation |
Test the proportional hazards assumption for a Cox regression model fit
(coxph
).
cox.zph(fit, transform="km", global=TRUE)
fit |
the result of fitting a Cox regression model, using the |
transform |
a character string specifying how the survival times should be transformed
before the test is performed.
Possible values are |
global |
should a global chi-square test be done, in addition to the per-variable tests. |
an object of class "cox.zph"
, with components:
table |
a matrix with one row for each variable, and optionally a last row for the global test. Columns of the matrix contain the correlation coefficient between transformed survival time and the scaled Schoenfeld residuals, a chi-square, and the two-sided p-value. For the global test there is no appropriate correlation, so an NA is entered into the matrix as a placeholder. |
x |
the transformed time axis. |
y |
the matrix of scaled Schoenfeld residuals. There will be one column per
variable and one row per event. The row labels contain the original event
times (for the identity transform, these will be the same as |
call |
the calling sequence for the routine. The computations require the original |
P. Grambsch and T. Therneau (1994), Proportional hazards tests and diagnostics based on weighted residuals. Biometrika, 81, 515-26.
fit <- coxph(Surv(futime, fustat) ~ age + ecog.ps, data=ovarian) temp <- cox.zph(fit) print(temp) # display the results plot(temp) # plot curves