Impact assessment in SLCA: Sorting the sLCIA methods according to their outcomes

Abstract

Background, aims, and scope Social Life Cycle Assessment (SLCA) is a tool assessing the social aspects of products and services. This article is a step forward from the Guidelines and wishes to clarify the different impact assessment (IA) methods covered in the Guidelines and how these different methods would provide different types of information regarding the social aspects of the product system. Methods The outcomes resulting from different sLCIA methods are discussed through the analysis of three methods covered by the Guidelines for SLCA (UNEP 2009): the Taskforce's method, Hunkeler's (2006) and Weidema's (2006). In order to highlight the different outcomes, we analyze the "nature" of the indicator results, the sources of the stressors, and the way the IA results are linked to the product system. Results Different results are provided depending on the sLCIA approach used. We stress that the use of impact pathways allows the assessment of social impacts. The Taskforce's method, which compares the state of the dimensions of the social context of the product system with international consensus, assesses "social performances." Regarding the sources of the stressors, the analysis needs to look at other levels than the unit process to capture the social issues. Finally, two approaches are used to connect the indicator results to the product system: one carrying the quantitative link between the inventory indicator and the functional unit all the way to the IA result through impact pathways, and the other, weighting the IA results according to the relative importance of an activity variable. Discussion The different features of the sLCIA methods result in different outcomes. Depending on the sources of the stressors, different levels are assessed. When the stressors are collected at an organizational level, e.g., country, sector, or enterprise, the unit assessed becomes the social context, which can be called "context units" parallel to the unit processes. SLCIA methods will also provide different outcomes depending on the characterization models used in the analysis: social impacts versus social performances. Finally, the difference between the outcomes according to the approaches used to link the IA results to the product system will require further reflections. Conclusions Two types of sLCIA are covered by the Guidelines. One uses Performance Reference Points allowing the evaluation of the relative position of the state of a dimension of a context unit in reference to an international consensus. The second one, closer to LCA, assesses the social impacts derived from the technical nature of the processes, through the use of impact pathways. Recommendations and perspectives Choosing between the feasibility of deriving social impacts from social variables through impact pathways or assessing a broader set of social issues through the use of semiquantitative indicators is an ongoing issue and requires further research. Currently, the choice of sLCIA methods is informed by the availability of the characterization models and the indicators. © 2010 Springer-Verlag.