Uncertainty in LCA: An estimation of practitioner-related effects

The aim of the paper is to quantitatively analyse a main source of uncertainty in LCA practice, i.e. the one due to the LCA practitioner. The same life cycle inventory dataset was used by six practitioners to independently compute six environmental impact categories with a cradle to grave approach, considering a red wine bottle produced by an Italian winery. To obtain the repeatability (r) and reproducibility (R) limits for each impact categories, LCA results were analyzed according to the ASTM E691-05 standard specifications. After a first stage of the study, in which relevant differences in the approach used and results were observed, all the practitioners considered the same system boundaries and processes, and, as a consequence, the results of all the impact categories became comparable. Nevertheless, the choice of different inventory datasets for describing the same process caused variations among the practitioners' outcomes. This study highlighted how the uncertainties due to the practitioner choices may significantly affect LCA results, especially when lack of information affects the data collection. The practitioner-related uncertainty should be considered in the same way as other uncertainty sources, especially when the Life Cycle impacts of a product are compared to the ones published in other studies. (c) 2020 Elsevier Ltd. All rights reserved.