ABSTRACT

A notion of virtual age might seem to be elusive but it can have sense when properly defined. Our recent paper (Finkelstein, 2007) was devoted to defining and discussing two types of virtual age: the statistical and the information-based virtual ages. The informationbased virtual age of a degrading object was defined via the observed degradation using its comparison with some average degradation, whereas the statistical virtual age was defined via comparison of the corresponding distribution functions of an item in different environments.