Skip to article frontmatterSkip to article content
Site not loading correctly?

This may be due to an incorrect BASE_URL configuration. See the MyST Documentation for reference.

What is an EEIO model?

Two grey boxes on the left feed arrows into a central box labeled EEIO model. The upper box, input-output tables, shows a small grid of cells and is described as dollars flowing between sectors and to final users, with the letters V, U, A, and L. The lower box, environmental extension, shows a row of shaded cells labeled CO₂, CH₄, and so on, and is described as greenhouse gases emitted by each sector, with the letters E, B, and C. The EEIO model traces emissions through every round of suppliers. An arrow from it leads to a highlighted box, emission factors D and N, in kilograms of CO₂e per dollar of purchases, by sector and country.

Figure 1:An EEIO model combines input-output tables with an environmental extension to produce emission factors.

Where EEIO comes from

EEIO grew out of economic input-output analysis when economist Wassily Leontief added the pollution generated by each sector to his model of the economy Leontief, 1970, and it has been a basis for carbon footprinting of nations, organizations, and products over the last few decades Minx et al., 2009. Cornerstone EEIO continues two of the longest-running US EEIO models, USEEIO and CEDA; see Origins of the Cornerstone EEIO.

The parts of the model

Each data component is put into a matrix, named by a letter that is common in input-output analysis and used throughout these docs (see Notation cheat sheet). Input-output analysis then combines the matrices with matrix algebra.

EEIO and life cycle assessment

An EEIO model has the same matrix structure as the models used for life cycle assessment (LCA) Suh, 2005. In both, a matrix of the inputs each activity needs is inverted to trace every upstream supplier, and a matrix of emissions per unit of each activity is multiplied through it. The difference is that EEIO describes sectors in dollars, where LCA usually describes individual processes in physical units. Because of this shared structure, EEIO data can serve as background data in LCA, as discussed in Ingwersen (2026).

Multi-regional models

A single-country model assumes imported products are made the same way, and with the same emissions, as products made at home. A multi-regional input-output (MRIO) model instead links countries’ input-output tables through international trade, so each import carries the supply chain and emissions as it was produced in the origin country. For the companies reporting to the Carbon Disclosure Project (CDP), in one study using an MRIO model instead of a U.S. single-region model raised their estimated upstream emissions by about 10% Davis et al., 2025. The Cornerstone model is an MRIO model; see From single-country tables to the multi-region model.

Further reading

For a book-length introduction to EEIO and its use in LCA, see Hendrickson et al. (2006).

References
  1. Leontief, W. (1970). Environmental Repercussions and the Economic Structure: An Input-Output Approach. The Review of Economics and Statistics, 52(3), 262–271. 10.2307/1926294
  2. Minx, J. c., Wiedmann, T., Wood, R., Peters, G. p., Lenzen, M., Owen, A., Scott, K., Barrett, J., Hubacek, K., Baiocchi, G., Paul, A., Dawkins, E., Briggs, J., Guan, D., Suh, S., & Ackerman, F. (2009). Input-Output Analysis and Carbon Footprinting: An Overview of Applications. Economic Systems Research, 21(3), 187–216. 10.1080/09535310903541298
  3. Suh, S. (2005). Developing a Sectoral Environmental Database for Input–Output Analysis: The Comprehensive Environmental Data Archive of the US. Economic Systems Research, 17(4), 449–469. 10.1080/09535310500284326
  4. Ingwersen, W. (2026). Considering Input-Output Derived Data as Background Life Cycle Inventory Data. Int J Life Cycle Assess, 31(9), 164. 10.1007/s11367-026-02735-9
  5. Davis, S. J., Dumit, A., Li, M., Maldonado, Y., Steffen, M., Stevenson, M., Boldyreva, T., & Suh, S. (2025). The Importance of Multiregional Accounting for Corporate Carbon Emissions. Nat Commun. 10.1038/s41467-025-67759-5
  6. Hendrickson, C. T., Lave, L. B., & Matthews, H. S. (2006). Environmental Life Cycle Assessment of Goods and Services: An Input-Output Approach. Resources for the Future. 10.4324/9781936331383
Cornerstone EEIO
Cornerstone EEIO
Cornerstone EEIO
Origins of the Cornerstone EEIO