Scope 3 Emissions Reporting: Enhancing Data Quality Through Supplier Engagement
Accurate Scope 3 emissions reporting depends on the quality of the information used to calculate emissions across the value chain. For many organisations, purchased goods and services represent a significant source of Scope 3 emissions, making supplier data particularly relevant. Moving from estimates towards more specific information can provide organisations with a more detailed understanding of where emissions arise across the value chain.
Why primary data matters for Scope 3 emissions reporting
Under the GHG Protocol Scope 3 framework, companies can use both primary and secondary data to calculate value-chain emissions. Primary data is specific to activities within a company’s value chain, such as information provided by suppliers about their materials, energy use or emissions. Secondary data, by contrast, typically comes from industry averages, databases or other generic sources.
For organisations seeking to enhance Scope 3 emissions reporting, primary data can provide a more specific picture of individual suppliers and activities. It may also support the tracking of changes over time and provide additional transparency on relevant emission sources.
Focus data collection where it matters most
Collecting supplier-specific information across an entire value chain may not always be practical. A more targeted approach can prioritise suppliers or activities that make the greatest contribution to the Scope 3 footprint.
For MM Group, purchased goods and services are the largest Scope 3 category. The 2025 Sustainability Statement notes that Scope 3 calculations rely mainly on secondary emission factors, while approximately 4.26% of Scope 3 emissions are based on primary emission factors.
Scope 3 Emissions Reporting and Supplier Data
Supplier data can provide a more detailed basis for emissions reporting and support informed procurement-related assessments. Information that reflects specific materials, processes or production sites may provide greater visibility than generic industry averages.
This does not mean secondary data becomes unnecessary. Where supplier-specific information is unavailable or insufficiently reliable, recognised secondary sources can continue to provide a basis for calculations. The GHG Protocol recommends considering factors including data quality, availability and the significance of the activity when selecting between primary and secondary data.
Using Supplier Data in Scope 3 Assessments
The value of primary data extends beyond calculating a footprint. More specific information can provide additional insight into supplier-specific activities, emission sources and areas that may warrant further analysis. It can therefore provide a more detailed basis for discussions relating to materials, processes and emissions data.
For MM Group, supplier engagement and data collection form part of its wider approach to understanding value-chain emissions and supporting responsible sourcing activities. MM has set a target to engage 80% of key suppliers by 2026 as part of its supplier engagement activities related to Scope 3 emissions.
Frequently Asked Questions on Scope 3 Emissions Reporting
Primary data is information relating to specific activities in a company’s value chain. It may include activity data collected by a supplier or emissions data calculated specifically for that supplier’s operations. This can provide a more specific representation of value-chain activities than industry-average or other secondary data.
Suppliers can provide information about the materials, energy and processes associated with purchased goods and services. This information may provide organisations with a more detailed basis for emissions calculations and support the monitoring of supplier-specific data over time.
No. Primary data may not always be available or sufficiently reliable. Secondary data can remain useful where supplier-specific information is unavailable, particularly for less significant activities. The GHG Protocol recommends selecting data according to factors such as the activity’s significance, data availability and quality.
Organisations can begin by identifying high-priority Scope 3 activities and the suppliers associated with them. Clear data requirements, guidance and regular communication can support the collection of supplier-specific information. A targeted approach may make data collection more manageable while progressively increasing coverage and data quality.
