<P> Data validity is an ongoing concern for life cycle analyses . Due to globalization and the rapid pace of research and development, new materials and manufacturing methods are continually being introduced to the market . This makes it both very important and very difficult to use up - to - date information when performing an LCA . If an LCA's conclusions are to be valid, the data must be recent; however, the data - gathering process takes time . If a product and its related processes have not undergone significant revisions since the last LCA data was collected, data validity is not a problem . However, consumer electronics such as cell phones can be redesigned as often as every 9 to 12 months, creating a need for ongoing data collection . </P> <P> The life cycle considered usually consists of a number of stages including: materials extraction, processing and manufacturing, product use, and product disposal . If the most environmentally harmful of these stages can be determined, then impact on the environment can be efficiently reduced by focusing on making changes for that particular phase . For example, the most energy - intensive life phase of an airplane or car is during use due to fuel consumption . One of the most effective ways to increase fuel efficiency is to decrease vehicle weight, and thus, car and airplane manufacturers can decrease environmental impact in a significant way by replacing heavier materials with lighter ones such as aluminium or carbon fiber - reinforced elements . The reduction during the use phase should be more than enough to balance additional raw material or manufacturing cost . </P> <P> Data sources are typically large databases, it is not appropriate to compare two options if different data sources have been used to source the data . Data sources include: </P> <Ul> <Li> soca </Li> <Li> EuGeos' 15804 - IA </Li> <Li> NEEDS </Li> <Li> ecoinvent </Li> <Li> PSILCA </Li> <Li> ESU World Food </Li> <Li> GaBi </Li> <Li> ELCD </Li> <Li> LC-Inventories.ch </Li> <Li> Social Hotspots </Li> <Li> ProBas </Li> <Li> bioenergiedat </Li> <Li> Agribalyse </Li> <Li> USDA </Li> <Li> Ökobaudat </Li> <Li> Agri - footprint </Li> <Li> Comprehensive Environmental Data Archive (CEDA) </Li> </Ul>

When conducting a life cycle analysis of manufactured goods