With the further assumption that people agree on the probability distribution of future cash flows, it is possible to have an objective capital asset pricing model. Even without the assumption of an agreement, it is possible to set rational limits on capital asset value.[1] For United States Federal government accounting, capital assets have been defined including land (including parklands), structures, equipment (including motor and aircraft fleets), and intellectual property (including software), that have an estimated useful life (also known as service life) of two years or more.