critical viewpoint on cost benefit analysis

cost benefit analysis basically involves evaluating the costs spent against the benefits derived.
this technique works on the principle that any cost expended or any amount spent, should give its benefits in accordance with the amount of money expended.
this analysis is done when a decision regarding high spending is to be done. in such situations, the various alternatives are identified, and then; the costs attached to selecting each of the alternative is weighed against the benefits that will be derived by choosing that particular alternative. in simpler words, it means selecting the best possible alternative among the ones available; by choosing the one that provides maximum benefits at minimum costs.
in relation to the advertising and media industry, this principle would be applied in the sense of choosing among the various media available, by selecting the one that will provide maximum and most effective advertising. pr, and promotions; with the minimum possible amount spent.