When should a company use supplier-specific data and when industry averages for Scope 3, under the Greenhouse Gas (GHG) Protocol?

Pick by goal. The GHG Protocol Scope 3 Standard says to select primary, supplier-specific data when the aim is reduction targets, tracking operations or engaging suppliers, and secondary, industry-average data when the aim is relative size and hot spots. It names three cases where secondary data is the general choice.

The two types, as the standard defines them

• Primary data is data from specific activities within a company's value chain. It includes data from suppliers and other partners: either primary activity data, or emissions data the supplier calculated for its own activities.
• Secondary data is data that is not from specific activities in the value chain: industry averages from published databases, government statistics, literature studies and industry associations, plus financial data, proxy data and other generic data.
• Proxy data counts as secondary. Specific data from one activity used to estimate another is still not specific to the activity being calculated.

Which goal points to which type

• Main goal is to set reduction targets, track performance from specific operations in the value chain, or engage suppliers: the company should select primary data.
• Main goal is to understand the relative size of Scope 3 activities, find hot spots and decide where to collect primary data: the company should select secondary data.
• For high priority activities, the standard says in general to collect high quality primary data, and to use primary data from suppliers for activities targeted for reductions, to track performance most effectively.

When secondary data is the general choice

1. Activities not prioritised by an initial estimate or other criteria.
2. Activities where primary data is not available, for example a partner cannot provide it.
3. Activities where the secondary data is of higher quality than the primary data on offer, for example when a partner cannot give data of enough quality.

What each type costs you

• Primary: a better picture of your own value chain, and it lets you track and benchmark partners. It may be costly, and it may be hard to determine or verify the source and quality of what partners supply.
• Secondary: can be more cost-effective and easier to collect, and can be useful for minor activities. It may not represent your activities, does not show operational changes partners make, and may limit your ability to track progress to targets.

If you are the supplier

My reading, not the standard's: when a buyer is only sizing its footprint, an industry average for what it buys from you is an accepted choice and your plant data is optional. When the buyer wants to show reductions from buying from you, only your own data can show them.

What the standard's Kraft Foods case shows

• Kraft Foods set out to build a complete first inventory for high-level strategic evaluation, using industry-average life cycle data matched to its own activity and purchase data
• It found Scope 3 was more than 90 percent of its combined Scope 1, 2 and 3 emissions, and that category 1 (purchased goods and services) was 70 percent of its Scope 3
• Per 100 units of combined emissions, that is Scope 3 above 90 and category 1 above 63 (0.70 x 90). The 63 is my arithmetic from the case's percentages

The case reports the secondary data approach gave reasonable accuracy, cost and speed, with a chance to update as better data came. Kraft also gave an uncertainty range for each category.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records. For a supplier, that gives primary fuel and power figures for the plant, which you can offer a buyer in place of an industry average.

• Filling gaps in Scope 3 data
• Rough Scope 3 data in the first year
• The five Scope 3 data quality indicators
• Collecting data from your own suppliers
• Free calculators

Sources: GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard, chapter 7 (Tables 7.3 and 7.5, section 7.3 and the Kraft Foods case), GHG Protocol Corporate Value Chain (Scope 3) Standard (ghgprotocol.org)

Last reviewed 2026-11-05. Wording is from the 2011 Scope 3 Standard. Ask your buyer which type it intends to use for you before you spend time on supplier-specific figures.