The proportional hazards assumption of the Cox model does sometimes not hold in practise.
An example is a treatment effect that decreases with time. We study a general multiplicative …

We present a new additive‐multiplicative hazard model which consists of two components.
The first component contains additive covariate effects through an additive Aalen model …

We propose an additive–multiplicative intensity model that extends the Cox regression
model as well as the additive Aalen model. Instead of having a simple baseline intensity the …

We derive the limiting distribution of the partial likelihood ratio under general conditions. The
multiplicative hazards models being fitted may be nonnested and misspecified. The true …

In estimating covariate coefficients for the Cox proportional-hazards model, there is a
nonzero probability for any finite sample that the maximum likelihood estimate will be …

We show how plots based on the residuals from a proportional hazards model may be used
to reveal the correct functional form for covariates in the model. A smoothed plot of the …

Often in medical studies of time to an event, the treatment effect is not constant over time. In
the context of Cox regression modeling, the most frequent solution is to apply a model that …

The partly linear additive Cox model is an extension of the (linear) Cox model and allows
flexible modeling of covariate effects semiparametrically. We study asymptotic properties of …

In power analysis for multivariable Cox regression models, variance of the estimated log‐
hazard ratio for the treatment effect is usually approximated by inverting the expected null …

New estimators for Cox regression that maximize a weighted version of the partial likelihood
are considered. Their asymptotic properties on the model are sketched. Estimators with …