Economic comparisons incremental

A preliminary economic analysis of the cell separation step indicates that membranes are two-fold more cost effective than centrifuges, and equivalent in cost to using a precoat vacuum filter for this application. Use of a precoat vacuum filter requires disposal of filter aid. This was not considered in the economic comparison, but could represent a significant incremental cost for preooat systems. 

Capital investments can also be selected on the basis of other measures of performance such as return on investment, internal rate of return, and benefit-cost ratio (or savings-to-investment ratio). Flowever, care must be taken in the application of these methods, as an incremental analysis is required to ensure consistent comparison of mutually exclusive alternatives. Also, rather than requiring a separate value to be calculated for each alternative, as in the case of the life-cycle cost method, these other methods incorporate the difference between two mutually exclusive alternatives within a single measure. For example, the net benefits measure directly pressures the degree to which one alternative is more economically desirable than another. 

Question eight addresses another extremely important area in economic analysis - that is, whether the analysis is incremental. For an analysis to be a truly meaningful comparison it is necessary to examine the additional costs that one drug or therapy imposes over another, compared with the additional effects or benefits it delivers. As with the issue of choice of the comparator drug, most economic guidelines worldwide stipulate that an economic analysis must be incremental. 

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