  In reliability theory and survival analysis, the residual entropy is known as
a measure suitable to describe the dynamic information content in stochastic
systems conditional on survival. Aiming to analyze the variability of such
information content, in this paper we introduce the variance of the residual
lifetimes, "residual varentropy" in short. After a theoretical investigation of
some properties of the residual varentropy, we illustrate certain applications
related to the proportional hazards model and the first-passage times of an
Ornstein-Uhlenbeck jump-diffusion process.
