Review: Critical Review and Verification of LCA
Time: Tuesday, 30/Aug/2011: 11:15am - 12:30pm
Session Chair: Walter Klöpffer
Session Chair: Philippe Osset
Location: Room 3
1st floor


“Critical review” and “Verification” cannot be used synonymously. A plea for a differentiated and precise use of the terms

Birgit Grahl1, Eva Schmincke2

1Industrial Ecology, Germany; 2Five Winds International, United States of America


Verification is a term originating from quality management (QMS). ISO 9000:2005 defines: “confirmation, through the provision of objective evidence, that specified requirements have been fulfilled”. Objective evidence in this context is “data supporting the existence or verity of something”.

The term “verification” was transferred to ISO 14025 and applied for handling the underlying LCA in Type III environmental declarations. Based on this application the term has been transformed by and by into a kind of synonym for critical reviews of LCA.

Since these terms have been defined in different contexts and by different communities their applications are prone to misunderstanding with respect to the exact content and/or activities intended.

Verification - philosophy of the term

In QMS and EMS the definition of requirements to be fulfilled as well as the concurrent objective evidence to be provided is not a problem. Requirements are made operational by defining either adequate documentation rules, tests or quantified indicators for targets.

Objective evidence in this case may be the documentation of management activities or the achieved indicator results. If requirements are clearly defined and the corresponding objective evidence clearly described, verification can be confined to stating the compliance between requirement and evidence.

Critical review - philosophy of the term

The critical review of LCA originates from a completely different context that is from the scientific peer review. The well known 5 criteria for a critical review according to ISO 14040 cannot be made operational in the same way as requirements and their objective evidence sketched out above.

The logic of a critical review can be better described as a falsification process rather than a positive compliance statement. As the philosophy of quality control of scientific work differs completely from the quality control of QMS or EMS the concept of verification borrowed from these systems is not applicable for the quality control of an LCA study


  • Since the philosophy of the terms critical review and verification is different they should not be used synonymously.
  • In future review of ISO 14025 a clear distinction between verifiable requirements and aspects that need to be critically reviewed should be provided.
  • This differentiation should also be communicated into the standardization projects referring to ISO 14025 in order to avoid the same misunderstandings there.

Comparison of the critical review process of LCA with the verification in ETS

Hans J. Garvens1,2

1LCA Consultant, Germany; 2Umweltbundesamt, Germany

The critical review of LCA is an ongoing process, done for more than a few LCA studies each year. Aside of the requirements from ISO and newly from the ILCD Handbook the reviews are conducted to the best practice by the members of the review panel. Nevertheless reviewers experience very different quality and personal intention of their colleagues in such processes. The submission will focus on LCI data and modeling verification as part of the LCA critical review.

As part of the European Emissions Trading System (ETS), verification of data has to be applied on the annual emission report and all applications. In Germany more than 1,600 annual emission reports are verified and submitted to the German Emissions Trading Authority, where they are checked for compliance. Some reports do not comply with the rules. In most of these cases the verifiers did not identify the mistakes.

Based on the evaluation of the data verification process in the European Emissions Trading System using a single verifier the quota of mistakes lead to a uncertainty assessment of the verification process. Based on these results the paper estimates the uncertainty of a three reviewers panel for the critical review of LCA studies.

International reference life cycle data system (ILCD): Review schemes for life cycle assessment

Kirana Chomkamsri, Marc-Andree Wolf, Rana Pant

Joint Research Centre, Italy

Quality and consistency of life cycle based decision support are essential in public policy and business context. Those can and should be supported by ‘critical review’ of underlying data and of Life Cycle Assessment (LCA) studies themselves. A review assesses whether a LCA study or related data set meets pre-defined requirements. A review can help avoiding errors, ensuring that all options or method requirements have been appropriately taken into account, and last but not least increasing acceptance by stakeholders. Whilst requiring efforts, failing to perform a thorough review can cost significantly more in the long term than you initially save. The principle requirements for reviews are briefly addressed in the ISO 14040 series. While other LCA-based standards define some review requirements in more detail, information on how to conduct the reviews or what qualifications are required from reviewers is scarce. Therefore, more specific requirements and guidance on reviewing Life Cycle Inventory and Life Cycle Assessment studies are provided in the International Reference Life Cycle Data System (ILCD) Handbook. Distinctions are made for the necessary level of review depending on the application context through a set of review schemes for 12 different cases. Differentiations are made with respect to the intended audience of the study (external, technical, or non-technical audience), the complexity and broadness of the assessment, and the necessary type of stakeholder involvement (depending e.g. whether product comparisons are included or not). The scope of review (“what”) and the method of review that shall be used to verify the fulfilment of the requirements (“how”), are specified in the ILCD Handbook. For how to do the review examples are provided, e.g. evidence collection by means of available documentation, cross-checks, verification and review of data source, calculations. More details are provided in the document “Review scope, methods and documentation for Life Cycle Assessment (LCA)”. Last but not least the review can be only as good as the reviewers. Therefore, the ILCD Handbook also provides requirements on the necessary qualifications of reviewers. For the ILCD Data Network, initially somewhat reduced "entry-level" requirements have been defined. All these ILCD review requirements conform to the LCA-related ISO standards. The presentation will inform about these requirements and procedures of the review as well as first experiences gained in several ongoing applications .

The intersection of critical review and assurance

Holly Lahd, Cynthia Cummis, Laura Draucker

World Resources Institute, United States of America

Critical Review, the process to verify whether an LCA it is consistent with the principles and has met the requirements for methodology, data, interpretation and reporting (ISO 14040), is an established practice among LCA practioners. Assurance, also known as verification, is an objective assessment of the accuracy, completeness, and presentation of a product inventory in conformance with a given standard. Verification is a standard practice for corporate GHG inventories. As more and more companies with corporate GHG inventory experience begin to perform product LCAs, how can existing assurance and critical review concepts be combined to serve this growing market?

The GHG Protocol Initiative, a joint partnership between The World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), is in the final stages of a three year, multi-stakeholder development process to publish the GHG Protocol Product Life Cycle Accounting & Reporting Standard. The goal of this standard is to provide a framework of requirements and guidance that enables companies and organizations to calculate and publicly report product life cycle GHG inventories.

The development of the Product Standard has led to new research in this area and new approaches on how to ensure the assurance process is robust and practical for products and supply chains. GHG Protocol Initiative representatives will discuss the assurance approach and requirements in the Product Standard, including a review of critical review as described in ISO 14040, verification concepts in the GHG Protocol Corporate Standard and ISO 14064-3, and the unique challenges independence and competency requirements pose for small to medium size companies conducting internal review.

Specific questions addressed in this presentation will include:

• How can existing scope 1 and 2 verification concepts and standards be applied to scope 3 and product LCAs?

• Can critical review meet the growing needs of companies conducting and communicating LCA information?

• What level of assurance is desirable in the marketplace for businesses and consumers, and what level is currently feasible?

Maintaining quality critical peer review (CPR) as the demand for life cycle assessments increases

Mary Ann Curran

US Environmental Protection Agency, United States of America

Environmental managers and government policy makers are becoming increasingly aware of the need to follow the holistic approach of Life Cycle Assessment (LCA) to move us in the right strategic direction to best achieve environmental sustainability. Along with this realization has been an explosive growth in the number of published LCA studies. Now the LCA community is faced with a serious challenge of meeting the growing demand for critical peer review (CPR) with an adequate supply of available, qualified experts to serve as technical reviewers.

A recent search in SCOPUS on the term “life cycle assessment” resulted in over 4,800 citations between 1991 and 2010. The table below shows the increase in the number of citations per year since 1999.

Year # Citations Year # Citations

1999 144 2005 420

2000 187 2006 375

2001 182 2007 448

2002 184 2008 499

2003 253 2009 649

2004 312 2010 >700

According to SCOPUS, the top five journals to publish on LCA produced around 1500 papers:

• International Journal of Life Cycle Assessment 828

• Journal of Cleaner Production 256

• Journal of Industrial Ecology 159

• Environmental Science & Technology 145

• Resource Conservation and Recycling 109

This paper addresses the key issues that LCA practitioners face in attempting to have LCA studies peer-reviewed, namely, the limited number of qualified reviewers and the growing popularity of the use of public databases, such as ecoinvent, which requires CPR to be handled in a different manner, since reviewers of studies cannot easily review all the underlying data and assumptions.

Although it has long been realized that CPR is an essential component of LCA, little guidance has been developed (Kloepffer 2005). In order to maintain the credibility of LCA methodology as a viable environmental management tool, clearer guidance for conducting CPR is needed. Especially, it is becoming increasingly important to have a better understanding of how to conduct a peer review of public databases and the life cycle inventories that are created from them.

Kloepffer, W (2005) The Critical Review Process According to ISO 14044-43: An Analysis of the Standards and Experiences Gained in the Application Int J LCA 10(2); pp98-102.