How to Collect Scope 3 Data From Suppliers

Collecting Scope 3 data from suppliers means building a repeatable process to request, gather, validate and store emissions and activity data from vendors across your value chain, mapped to the GHG Protocol's 15 Scope 3 categories. It requires prioritising suppliers by emissions impact, choosing an appropriate data collection approach, and running structured outreach with clear templates and deadlines.

Summary

• Collecting Scope 3 data is a repeatable process, not a one-off survey: map, prioritise, request, validate, store.
• Response rates to a first request are typically low, so coverage builds over several cycles rather than in one.
• Make data requests proportionate to materiality, supplier readiness and how the data will be used.
• Concentrate deeper engagement on the suppliers and categories that matter most, while using appropriate estimates for the long tail.

What Are the Steps to Collect Scope 3 Data From Suppliers?

Collecting supplier data is a sequential process, not a one-off survey. The steps below describe the approach most companies follow when gathering Scope 3 emissions data across their supply chains.

Step 1: Map Your Supply Chain Against the 15 Categories

Identify which of the GHG Protocol's 15 Scope 3 categories apply to your business, and which suppliers or activities sit within each one. This mapping determines where to focus data collection effort.

Step 2: Prioritise Suppliers by Emissions Impact

Supplier prioritisation typically considers spend, emissions intensity of the category, and strategic importance to the business. This helps focus limited resources on suppliers with the greatest emissions footprint.

Step 3: Choose Your Data Collection Method

The appropriate method will depend on the category, materiality and data available. Companies may use a combination of estimates, activity data and supplier-specific information across their inventory.

For a deeper explanation of the calculation methods, see: How to Calculate Scope 3 Emissions: Methods and Data Explained.

Step 4: Build a Supplier Communication and Request Strategy

Structured data requests typically include a clear submission deadline, a defined template, and an explanation of why the data is being requested. These elements improve response quality and help suppliers understand the context for the request.

Step 5: Review, Validate and Store the Data

Submitted data should be checked for completeness, consistency with prior periods, and plausibility against known activity levels. Store it in a format that supports year-on-year comparison and audit review.

Step 6: Report Against the 15 Categories With Disclosed Methodology

If you report under ISSB standards, paragraph 29(a)(ii) of IFRS S2 requires the measurement itself to follow the GHG Protocol Corporate Standard, unless a jurisdictional authority or your exchange requires another method. That is what ties the disclosure obligation to the calculation methods above.

The GHG Protocol requires companies to disclose the methodologies, assumptions and data sources used for each category, including the percentage of emissions calculated from primary supplier data versus secondary or spend-based estimates. This transparency requirement applies regardless of which method dominates your calculation.

What Makes Scope 3 Data Collection Difficult?

Several structural barriers constrain Scope 3 data availability across supply chains.

• Survey fatigue: suppliers often receive overlapping ESG requests from multiple buyers using different templates and metrics.
• Limited SME capacity: smaller suppliers frequently lack the financial and human resources, or the technological infrastructure, to respond in detail.
• Low response rates: a first request typically reaches far more suppliers than it gets usable answers from, so coverage builds over several cycles.
• Immature systems: many suppliers still rely on spreadsheets rather than structured emissions tracking systems, limiting data consistency.

Don't ask every supplier for the same level of data. Focus deeper engagement on suppliers and categories that matter most, and make requests proportionate to materiality, supplier readiness and how the data will be used.

Scope 3 Becomes a Repeatable Value-Chain Data Process

As Scope 3 reporting matures, the bottleneck often shifts. At the beginning, the question is: "How do we calculate our Scope 3 emissions?" Later, it becomes: "How do we systematically improve the data behind that calculation?"

Better value-chain data requires companies to decide who to engage, what information to request, how to accommodate different levels of reporting readiness, how to validate what comes back and how to maintain the information over successive reporting cycles. Sustainability teams cannot solve all of this alone.

Improving value-chain data requires coordination across teams and partners

Building and improving a Scope 3 inventory requires different functions to contribute the data, relationships and expertise they already own:

• Sustainability Team: sets the reporting requirements, methodology and data-quality priorities.
• Procurement Team: holds many supplier relationships and can help make data requests workable within existing commercial processes.
• Finance Team and other data owners: provide spend, investment and control information and can support consistency and auditability.
• Suppliers and other value-chain partners: hold much of the operational and activity data needed to improve the inventory.
• Technology and Data Infrastructure Team: can help standardise requests, structure responses, maintain data trails and make information reusable across relevant business processes.

For companies where purchased goods and services are material, this is the point at which Scope 3 can become substantially a supplier-data and engagement challenge. The sustainability team may know what information it wants, but collecting it consistently across hundreds or thousands of suppliers requires a process that procurement and suppliers can actually work with.

The challenge is amplified when suppliers receive similar sustainability requests from multiple customers, financiers and reports in different formats. Repeated requests create duplicated work and make it harder to maintain consistent definitions and a reliable data trail.

This is where structured and interoperable sustainability data can help. If core information is captured using common definitions and can be reused, with appropriate permissions, across reporting, procurement and financing use cases, enterprises can spend less time reformatting data and more time improving its quality and acting on what it shows.

Scope 3 is not only a sustainability-team problem. As reporting matures, better Scope 3 data increasingly depends on collaboration across sustainability, procurement, finance, internal data owners and external value-chain partners.

Frequently Asked Questions

What should I do about suppliers who never respond?

Estimate them and record that you did. A documented secondary estimate for a non-responding supplier is a normal part of a Scope 3 inventory. Chasing every supplier to a reply costs more than the precision is worth for most of the tail.

Should I collect supplier data with assurance in mind?

Yes. Even where assurance is not currently required, maintaining clear data sources, methodologies and an audit trail can make future review and assurance easier. Build traceability into the collection process rather than trying to reconstruct it later.

How to Start

Collecting Scope 3 data is a process problem before it is a calculation problem, and it gets harder the more suppliers you add.

Gprnt is the shared sustainability data infrastructure Singapore built for exactly that: a way for suppliers to report structured data once and for buyers, banks and reporting programmes to draw on it with permission, instead of each party collecting the same information separately. It feeds an enterprise's existing calculation and reporting stack rather than replacing it. To see how it applies to your value chain, visit gprnt.ai.

References

• GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard (2011)
• GHG Protocol, Technical Guidance for Calculating Scope 3 Emissions, Category 1: Purchased Goods and Services
• CDP, Technical Note: Relevance of Scope 3 Categories by Sector (2022)
• IFRS S2 Climate-related Disclosures (2023)
• SBTi, Criteria and Recommendations for Near-Term Targets
• European Commission, Corporate Sustainability Reporting Directive: implementing and delegated acts
• ACRA and SGX RegCo, Extended Timelines for Most Climate Reporting Requirements (August 2025)