The 8th SETAC LCA Case Studies Symposium took place in Brussels on 30 November 2000 under the theme “Increasing credibility of LCA.” Its discussions highlighted how uncertainty and data quality affect the usefulness of life cycle assessment results. Participants considered data quality indicators helpful for communicating uncertainty, while detailed quantitative analyses could be difficult for decision-makers to interpret. Several speakers also emphasised that uncertainty can arise from modelling choices, not only from inventory data.
Bo Weidema’s summary argues that uncertainty must first be understood before it can be reduced. This makes it possible to direct data collection towards the largest uncertainties and continue until the remaining uncertainty cannot reasonably be reduced. Scenarios were suggested as one way to examine and quantify modelling uncertainty.
A separate session explored how LCA can inform different decisions. Presentations described using large databases to identify areas of concern and develop general guidance for non-experts, as well as involving stakeholders and accounting for decision-makers’ need for flexibility. The discussions also exposed a tension between simple, single-parameter communication and the greater credibility that can come from using several methods. The report stresses that results should explain how conclusions depend on assumptions and that answers may not be clear-cut.
The symposium discussion concluded that critical review can improve both the quality and credibility of an LCA. For larger studies, the report recommends interactive review at several stages: after goal and scope definition, after data collection, and after interpretation. When planned alongside the study and supported by close contact between the practitioner and reviewer, this approach can make the work more efficient. Cost, time and the limited availability of experienced, independent reviewers were identified as barriers.
The panel unanimously recommended developing guidance for critical review, including how review results should be communicated, and exchanging experience to document good practice and practical solutions.
