Why perform a critical review of an LCA?
Critical review of life cycle assessments is all about credibility. Therefore, the ISO 14044 standard requires critical reviews to be performed on all life cycle assessments supporting a comparative assertion disclosed to the public.
"Critical review" is the ISO 14040-terminology for a peer review. Traditionally, peer reviews are known from the international scientific journals, where submitted articles are subjected to critical scrutiny by anonymous colleagues (peers) before being accepted for publication - often after considerable adjustments. Since it is difficult to determine objective criteria for scientific quality, the subjective - but professional - judgement of peers becomes the ultimate quality assurance for scientific work.
What life cycle assessments have in common with scientific work, is the difficulty of establishing objective quality criteria. Many of the judgements made in the course of a life cycle assessment cannot be said to be true or false, but only more or less justifiable. Therefore, the ultimate quality judgement can only be subjective - although based on professional experience.
How to perform a critical review?
A critical review may be a simple peer review of the final report, or it may be a more integrated quality assurance involving typically three review steps: After the scope definition, after the data collection, and after the conclusion is made. The advantage of this interactive procedure is that problems can be corrected at an early stage, before resources are expended on work which later turns out to be inadequate. An interactive review should not be more expensive than a post-study review - on the contrary: It is less time consuming to guide a study onto the right track from its beginning, than to figure out how a complicated result has been influenced by dubious assumptions, or to reconstruct a missing calculation, once the study is finished.
For details on the procedure, see our "Guidelines for critical review of product life cycle assessments"
Example of a critical review
- B P Weidema, A Inaba, G A Keoleain (2002) ยท Critical review of the 2002 update of the IISI Worldwide LCI Database for Steel Industry Products. Pp. 82-85 in World Steel Life Cycle Inventory, Methodology Report 1999-2000. Brussels: International Iron and Steel Institute.