Scope 3: Purchasing Data Entry

Purchasing data is a newly available scope 3 data entry option in SIMAP. It provides the option to enter dollars spent on any purchasing category at your organization to calculate your scope 3 emissions. See the purchasing categories page for a full list of the purchasing categories available in SIMAP.

What is the data source?EPA EEIO_0.png

The purchasing data emission factors are from the US EPA's Environmentally Extended Input-Output (EEIO) database. The EPA states that their EEIO model uses "combined economic-environmental models. The models use data on inputs to and outputs from industries and their final consumption and value added in the form of input-output tables from the Bureau of Economic Analysis. These tables are paired with environmental data on resource use and releases of pollutants from various public sources in the form of satellite tables, as well as indicators of potential environmental and economic impact, using standard algorithms from input-output analysis. USEEIO is one form of a life cycle assessment model."

The EEIO approach essentially takes US national greenhouse gas emissions data and allocates it to 460 spend-based categories. The EEIO database includes commodity and industry factors, and it provides the emissions factors with and without margins. The SIMAP database uses the following emission factor types from the EPA EEIO database:

  • Commodity factors since organizations are the purchasers of commodities, which the EPA defines as "goods and services produced by industries in an economy." The industry factors are more relevant for the "...sectors that produce goods and services in an economy."
  • Emissions factors with margins to provide a more comprehensive estimate of emissions across the supply chain, including the emissions associated with transporting, storing, and selling a commodity.
  • Emissions factors for CO2, CH4, N2O, and other GHG. The 'other GHG' category includes refrigerants, chemicals, and other greenhouse gases. Since SIMAP does not have an emissions category for other GHG, these emissions were added to the CO2 emissions factors as CO2-equivalents.
  • 2016 emissions factors, which is the most recent data set available from the EPA EEIO database (version 1.1.1). The 2016 values are applied across all years and will be updated in more recent years as new data sets are available. These 2016 emissions factors are all normalized to 2018 USD. SIMAP includes inflator/deflator factors to normalize all dollar entry by year to 2018 USD. See the table below for more information.

On August 9th, 2023, SIMAP updated to version 1.1.1 of the EPA EEIO emission factor database. Prior to this update, we had been using version 1.0 of the EPA's EEIO emissions factors. We continue to use the same category names to avoid confusion. An even newer version (1.2) is now available from EPA, and we will incorporate that update soon into SIMAP. Version 1.2 (released April 2023) reports 2019 emissions factors in 2021 USD and also includes more detailed goods and services categories.

Where can I find my organization's purchasing data? 

The best source for your organization's purchasing data is your annual budget. This annual accounting should show your major spending categories, and you can often find more detailed breakdowns as needed from specific departments. 

If I have a data in both dollars and weights, which should I use? 

When available, it is best to use weight-based data because it better reflects the actual emissions. Using purchasing data in dollars spent introduces uncertainty due to the variability of prices. However, dollar amounts can fill important gaps in an emissions inventory and provide an order-of-magnitude estimate that helps identify the largest categories. From the spend-based analysis, you can then determine which categories should be a priority for obtaining more detailed weight-based data.

Important notes about entering purchasing data

  • Avoid double-counting: Be sure to only enter an activity data set one place in SIMAP to avoid double counting of emissions. For example, if you have a food purchase data set available in dollars and in weights, only enter one of those data sets.
  • Consider uncertainty: The spend-based approach with purchasing data has inherent uncertainty due to the significant range of prices across time and across locations for the same product. Use purchasing data for an order of magnitude estimate and be sure to note the uncertainty in your reporting.

What purchasing categories are available in SIMAP? 

SIMAP includes both the Summary and Detailed categories available in the EPA EEIO database. There are 60 summary categories, and we mapped the -- detailed categories to those summary categories. After you select one of the 60 summary categories from the first drop-down on a purchasing data entry page, the detailed categories will then appear in the second drop-down. There is always an average category available for each summary category.

The list below shows all 60 summary categories. To view the summary and detailed categories, see this page or download this Excel file.

  • Accommodation 

  • Administrative and support services 

  • Air transportation 

  • Ambulatory health care services 

  • Amusements, gambling, and recreation industries 

  • Apparel and leather and applied products 

  • Broadcasting and telecommunications 

  • Chemical products 

  • Computer and electronic products 

  • Computer systems design and related services 

  • Construction 

  • Data processing, internet publishing, and other information services 

  • Educational services 

  • Electrical equipment, appliances, and components 

  • Fabricated metal products 

  • Farms 

  • Federal Reserve banks, credit intermediation, and related activities 

  • Food and beverage and tobacco products 

  • Food and beverage stores 

  • Food services and drinking places 

  • Forestry, fishing, and related activities 

  • Funds, trusts, and other financial vehicles 

  • Furniture and related products 

  • General merchandise stores 

  • Hospitals  

  • Housing 

  • Insurance carriers and related activities 

  • Legal services 

  • Machinery 

  • Management of companies and enterprises 

  • Mining, except oil and gas 

  • Miscellaneous manufacturing 

  • Miscellaneous professional, scientific, and technical services 

  • Motion picture and sound recording industries 

  • Motor vehicle and parts dealers 

  • motor vehicle, bodies and trailers, and parts 

  • Nonmetallic mineral products 

  • Nursing and residential care facilities 

  • Oil and gas extraction 

  • Paper products 

  • Performing arts, spectator sports, museums, and related activities 

  • Petroleum and coal products 

  • Pipeline transportation 

  • Plastics and rubber products 

  • Primary metals 

  • Printing and related activities 

  • Publishing industries, except internet (includes software) 

  • Rail transportation 

  • Rental and leasing services and lessors of intangible assets 

  • Securities, commodity contracts, and investments 

  • Social assistance 

  • Support activities for mining 

  • Textile mills and textile product mills 

  • Transit and ground passenger transportation 

  • Truck transportation 

  • Utilities 

  • Warehousing and storage 

  • Waste management and remediation services 

  • Water transportation 

  • Wholesale trade 

  • Other real estate 

  • Other retail 

  • Other services, except government 

  • Other transportation and support activities 

  • Other transportation equipment 

Which purchasing category should I use? 

Use the information from your annual budget to map to the most similar summary category from the list above. You can then view the detailed category list to see if there is a more specific category to match your purchasing data. 

How to enter your purchasing data

Navigate to the Data Entry tab and select a scope 3 category from the panel on the left. Click the green button for 'Purchasing Data' to enter purchasing data for that category. Note that you will have two options for your data entry:

  • US Dollars
  • MT eCO2 (metric tons of carbon dioxide equivalents)

You can also enter any purchasing data on the 'All Purchasing Data' page at the end of the scope 3 menu.

Inflation factors used in SIMAP

The EPA EEIO data set uses 2016 data adjusted to 2018 US dollars. In SIMAP, users should enter dollars spent in the reporting year. SIMAP will then adjust the dollars entered to 2018 US dollars using inflation and deflation factors from the US Bureau of Labor Statistic's Consumer Price Index (CPI) Inflation Calculator. This data set was used for inflation and deflation because this data set best reflects the change in price that consumers, such as organizations, pay for goods and services.

Inflation and deflation factors relative to 2018 for purchasing data calculations

Year Factor
1990 0.51
1991 0.54
1992 0.56
1993 0.58
1994 0.59
1995 0.61
1996 0.62
1997 0.64
1998 0.65
1999 0.66
2000 0.68
2001 0.71
2002 0.71
2003 0.73
2004 0.75
2005 0.77
2006 0.8
2007 0.82
2008 0.85
2009 0.85
2010 0.87
2011 0.89
2012 0.91
2013 0.93
2014 0.94
2015 0.94
2016 0.96
2017 0.98
2018 1
2019 1.02
2020 1.04
2021 1.06
2022 1.13
2023 1.21

Source: US Bureau of Labor Statistics CPI Calculator

Approach: Recorded inflation/deflation factors relative to 2018 for all years from 1990 to the present (2023). Used the month of January. For future years, used average rate of inflation from the past 10 years for projections.


US EPA. United States Environmentally-Extended Input-Output models. Last accessed February 2023.

[US EPA 2020] Ingwersen, W. AND M. Li. Supply Chain Greenhouse Gas Emission Factors for US Industries and Commodities. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-20/001, 2020.

US Bureau of Labor Statistics. Consumer Price Index (CPI) Inflation Calculator. Last accessed February 2023.