The reason to perform an LCA is essentially to use it in support of a decision. A decision gives rise to a change somewhere in society compared to a scenario in which this decision was not taken. The key requirement for the LCA in any application is therefore, that it shall reflect the environmental change caused by the decision. It is found, that the need to differentiate LCA methodology for the use in different applications is born by a few key characteristics of the decision to be supported.
The first key characteristic is the environmental consequence of the decision, i.e. the nature and extent of the environmental change caused by the decision. When modelling the environmental change, its extent in time and space will differ between decision types, thus giving rise to different requirements, primarily for the scoping and inventory phases of the LCA. Furthermore, some decisions will imply trade-offs between different impact categories, while others will not, thus causing different requirements for the impact assessment. The second key characteristic is the social and economic consequence of the decision, the magnitude of which will influence the need for certainty, transparency and documentation. The third characteristic is the context in which the decision is taken, including the decision maker and interested parties, implicitly influencing the impact assessment and weighting.