The Analytic Hierarchy Process is one of the most widely exploited decision making methods in cases when the decision (the selection of given alternatives and their prioritizing) is based on several criteria/subcriteria. The method application can be explained in four steps: 1) The hierarchy model of the decision problem is developed in such a way that the goal is positioned at the top, with criteria and subcriteria on lower levels, and finally alternatives at the bottom of the model. 2) After the hierarchy has been constructed, on each hierarchy structure level the pair-wise comparisons should be done by comparing all pairs of the elements belonging to the same node, starting with the top of the hierarchy and working this way to the lowest level. This procedure is supported by Saaty-es fundamental scale of absolute numbers by which the ratios of relative importance are represented. On the basis of the pair-wise comparisons, local importance (expressed as priorities for alternatives and weights for criteria) of elements of the hierarchy structure are calculated. 3) Finally, these results are synthesized into an overall priority list of alternatives. Decision maker is allowed to change preferences and to test the results if the inconsistency level is considered high. 4) The sensitivity analysis is also carried out. Sensitivity analysis is used to determine how the priorities of the alternatives change with respect to the importance of the criteria or sub-criteria [7]. As was indicated, both the net present value and the internal rate of return methods result in identical
decisions to either accept or reject an independent project. This is true because the net present value is
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greater than zero if and only if the internal rate of return is greater than the required rate of return, k. In the
case of mutually exclusive projects, however, the two methods may yield contradictory results; one project
may have a higher internal rate of return than another, at the same time a lower net present value. The
outcome depends on the assumptions the decision maker chooses to make about the implied reinvestment
rate for the net cash flows generated from each project. Consequently, in the absence of capital rationing, the
net present value approach is normally superior to both the profitability index and the internal rate of return
when choosing among mutually exclusive investments [8].
The final potential difficulty related to implementing the alternative methods of project evaluation and
selection that we will discuss concerns capital rationing. Capital rationing occurs any time there is a budget
ceiling, or constraint, on the amount of funds that can be invested during a specific period, such as a year.
Such constraint is prevalent in a number of firms, particularly in those that have a policy of internally
financing all capital expenditures. Another example of capital rationing occurs when a division of large
company is allowed to make capital expenditures only up to a specified budget ceiling, over which the
division usually has no control. With a capital rationing constraint, the firm attempts to select the
combination of investment proposals that will provide the greatest increase in the value of the firm subject to
not exceeding the budget ceiling constraint. Because of the budget constraint, you cannot necessarily invest
in all proposals that increase the net present value of the firms; you invest in an acceptable proposal only if
the budget constraint allows such investment. As you can see, selecting projects by descending of
profitability index allows you to select the mix of projects that adds most to firm value when operating under
a single-period budget ceiling [9].
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