Extract cumulative coefficients (cumulative hazard differences)

These functions are designed to extract (or mimic) the cumulative coefficients usually used in additive hazards models (Aalen model) to depict (time-varying) covariate effects. For PAMMs, these are the differences between the cumulative hazard rates where all covariates except one have the identical values. For a numeric covariate of interest, this calculates \(\Lambda(t|x+1) - \Lambda(t|x)\). For non-numeric covariates the cumulative hazard of the reference level is subtracted from the cumulative hazards evaluated at all non reference levels. Standard errors are calculated using the delta method.

get_cumu_coef(model, data = NULL, terms, ...)

# S3 method for class 'gam'
get_cumu_coef(
  model,
  data,
  terms,
  time_var = "tend",
  interval_length = "intlen",
  ...
)

# S3 method for class 'aalen'
get_cumu_coef(model, data = NULL, terms, ci = TRUE, ...)

# S3 method for class 'cox.aalen'
get_cumu_coef(model, data = NULL, terms, ci = TRUE, ...)

Arguments

model: Object from which to extract cumulative coefficients.
data: Additional data if necessary.
terms: A character vector of variables for which the cumulative coefficient should be calculated.
...: Further arguments passed to methods.
time_var: Name of the evaluation time variable in data. Defaults to "tend".
interval_length: Name of the interval-length variable in data. Defaults to "intlen".
ci: Logical. Indicates if confidence intervals should be returned as well.