Our paper extends prior work on abandonment and replacement policies by analyzing the effects of both the Darby and the Fisher interest rate hypotheses. In most of the new cases developed, the effect of increased inflation on economic life is ambiguous. In the abandonment problem, we find a greater tendency under the Fisher hypothesis than under the Darby hypothesis for increased inflation to result in an extension of economic life. In contrast, for the replacement problem, there is a greater tendency under the Fisher hypothesis (than under Darby) for inflation to shorten the asset holding period.

Yitzhaki [19] recently developed two portfolio selection criteria (EG and EΓ) based on the mean and Gini's mean difference. Similar to mean-variance(EV), the EG criterion uses two summary statistics to describe the probability distribution of a risky prospect, the mean and one-half Gini's mean difference. Gini's mean difference is defined as the average of the absolute differences between all possible pairs of observations of a random variable. Yitzhaki's development concentrated on the theoretical aspects of EG and EΓ and the theoretical relationships among EG, EΓ, EV, and stochastic dominance (SD) selection criteria. He did not address either the empirical properties of EG and EΓ or the relationship between the empirical efficient sets of EG and EΓ and other portfolio selection criteria. Yitzhaki suggested that the next step in the development and application of his proposed selection criteria should be an empirical investigation of how the EG and EΓ criteria compare with other selection criteria.

Numerous studies in recent years have emphasized the importance of accounting properly for abandoment value in capital budgeting (see [1], [4], [7], [10], and [11]). For a variety of reasons, a project need be neither physically exhausted nor have negative cash flows to be abandoned. Robichek and Van Home [10] suggested that a project should be abandoned in any period in which the present value of future cash flows does not exceed its abandonment value. In a modification of this rule, Dyl and Long [4] proposed that the firm give consideration to all possible future abandonment opportunities. They argued that abandonment need not occur at the earliest possible date that the abandonment condition is satisfied, but rather at the date that yields the highest NPV over all future abandonment possibilities. A generalization of these models was offered by Bonini [1], who developed a dynamic programming model to analyze investment projects with abandonment possibilities and uncertain cash flows. More recently, Gaumnitz and Emery [7] compared the abandonment decision to the like-for-like replacement decision and noted that the correct model for a particular case depends on the suitability of the assumptions.