ah: Fitting semiparametric additive hazards regression models.
In ivtools: Instrumental Variables

Description Usage Arguments Details Value Note Author(s) References Examples

ah is a wrapper around the ahaz function in the ahaz package, with a more user-friendly and standard interface. Refer to the manual for ahaz for details.

1	ah(formula, data, weights, robust=FALSE)

`formula`	an object of class "formula": a symbolic description of the model to be fitted.
`data`	a data frame containing the variables in the model.
`weights`	an optional vector of prior weights to be used in the fitting process.
`robust`	robust calculation of variance; see manual for `ahaz`.

See manual for ahaz.

An object of class "ah" is a list containing the same elements as an object of class "ahaz", plus

`call`	the matched call.
`formula`	the formula argument.
`coefficients`	a named vector of estimated coefficients.
`vcov`	the variance-covariance matrix for the estimated coefficients.
`incl`	the `ahaz` function does not allow for missing data. Thus, if `data` contains rows with missing data on any of the variables in the model, then these rows are excluded before calling `ahaz`. `incl` is a vector containing the rownames of those rows that are included in the analysis, that is, the rows with no missing data on any of the variables in the model.

The ahaz function does not allow for ties. Thus, before calling ah any ties have to be manually broken.

Arvid Sjolander.

Lin D.Y., Ying Z. (1994). Semiparametric analysis of the additive risk model. Biometrika 81(1), 61-71.

require(ahaz)

##This example is adapted from the example given for the ahaz function 
##in the ahaz package 

data(sorlie)

# Break ties
set.seed(10101)
sorlie$time <- sorlie$time+runif(nrow(sorlie))*1e-2

# Fit additive hazards model 
fit <- ah(formula=Surv(time, status)~X13+X14+X15+X16+X17+X18+X19+X20+X21+X22, 
  data=sorlie)
summary(fit)