COMPARAÇÃO DE ALTERNATIVAS COM DIFERENTES ESCALAS DE INVESTIMENTO: UM CASO DE PERDA DE MEMÓRIA EM ECONOMIA DA ENGENHARIA?

Abstract

Engineers evaluate alternatives. Facing a set oftechnically equivalent solutions of a problem, but withdifferent scales, they must choose the best alternative.Economic criteria, with increasing dominance of those thatdiscount cash flows, are used. It is then usual to arise analleged conflict among alternatives ranking producedaccording to NPV (net present value) or IRR (internal rateof return): alternative with larger investment shows largerNPV, alternative with smaller investment promises greaterIRR. Careful analysis reveals this to be an apparentcontradiction. Friedrich and Vera Lutz expounded andsolved this issue in their book “The Theory of the Investmentof the Firm”, published in 1951. Nevertheless, the majority –if not all – of the Engineering Economy textbooks maintainsthe existence of a (false) conflict that would demand“incremental analysis” – this totally unnecessary. A stepbackwards in theory and practice. Has the knowledgeproduced by the Lutzes been lost?

Index Terms - production engineering, engineering economy, optimal investment scale, loss memory.