Midpoints versus endpoints: The sacrifices and benefits

  • Jane C. Bare
  • Patrick Hofstetter
  • David W. Pennington
  • Helias A. Udo de Haes
State-of-the-art: LCIA Life cycle impact assessment workshop summary

DOI: 10.1007/BF02978665

Cite this article as:
Bare, J.C., Hofstetter, P., Pennington, D.W. et al. Int. J. LCA (2000) 5: 319. doi:10.1007/BF02978665


On May 25–26, 2000 in Brighton (England), the third in a series of international workshops was held under the umbrella of UNEP addressing issues in Life Cycle Impact Assessment (LCIA). The workshop provided a forum for experts to discuss midpoint vs. endpoint modeling. Midpoints are considered to be links in the cause-effect chain (environmental mechanism) of an impact category, prior to the endpoints, at which characterization factors or indicators can be derived to reflect the relative importance of emissions or extractions. Common examples of midpoint characterization factors include ozone depletion potentials, global warming potentials, and photochemical ozone (smog) creation potentials. Recently, however, some methodologies have adopted characterization factors at an endpoint level in the cause-effect chain for all categories of impact (e.g., human health impacts in terms of disability adjusted life years for carcinogenicity, climate change, ozone depletion, photochemical ozone creation; or impacts in terms of changes in biodiversity, etc.). The topics addressed at this workshop included the implications of midpoint versus endpoint indicators with respect to uncertainty (parameter, model and scenario), transparency and the ability to subsequently resolve trade-offs across impact categories using weighting techniques. The workshop closed with a consensus that both midpoint and endpoint methodologies provide useful information to the decision maker, prompting the call for tools that include both in a consistent framework.


Categories of impact cause-effect chain decision making endpoint modeling global warming potentials ISO 14042 LCA LCIA Life Cycle Assessment (LCA) Life Cycle Impact Assessment (LCIA) midpoint modeling ozone depletion potentials photochemical ozone (smog) creation potentials 

Copyright information

© Ecomed Publishers 2000

Authors and Affiliations

  • Jane C. Bare
    • 1
  • Patrick Hofstetter
    • 2
  • David W. Pennington
    • 3
  • Helias A. Udo de Haes
    • 4
  1. 1.U.S. Environmental Protection Agency (EPA)National Risk Management Research LaboratoryCincinnatiUSA
  2. 2.ORISE Research Fellow, U.S. EPANational Risk Management Research LaboratoryCincinnatiUSA
  3. 3.Laboratory of Ecosystem ManagementEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
  4. 4.Centre of Environmental Science (CML)Leiden UniversityLeidenNetherlands

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