Objectivity and Purpose While LCA does carry an aura of objectivity, there is in fact a large measure of subjectivity to it. This is not just because of the very bias of LCA in selecting certain impact categories, but also because of the complexity of the interrelationships involved. This complexity requires LCA practitioners to apply simplifying assumptions at each stage. Various international organizations, like SETAC and ISO mentioned above, are constantly trying to standardize these assumptions in order to bring some uniformity and comparability into assessment. At the same time, new software tools are being developed to provide needed data for the assessment. Nevertheless, material selection remains almost as much an art as a science. The complexity of comprehensive LCA has also held back its practical use by industry, contractors, designers and consumers. This has spawned initiatives to simplify or streamline it to allow it to be applied more widely. There has been some negative reaction to this by those who fear oversimplification, but other researchers (J. A. Todd & Curran, 1999) have argued that streamlining is part of any LCA. There is a growing recognition that full-scale and streamlined LCA are not so much two separate things, but a continuum along which many appropriate forms of LCA can exist. Proponents of this viewpoint argue that the bigger problem is that few protocols have been developed to guide the process of simplifying, particularly at the scope and goal stage, without compromising the integrity of the study. Subjectivity is a factor even in the most objective part of an LCA, the second or inventory (LCI) stage where decisions are made about the key input and output accounts. Depending on the product, there is some leeway in the very choice of accounts. In