Abstract
In this note the value of parametric changes in hazard rates is analyzed. Two different kinds of changes, sudden or 'blip' changes and persistent changes, respectively, are considered within a model in which both the marginal rate of time preference and the survival probability are age-dependent. Numerical simulations are used to illustrate the fact that the magnitude of the pure time preference determines the age- profile of the value of parametric changes in the survival probability. The value of such changes is decreasing or increasing in age depending on the magnitude of the time preference.