Improving Scope 3 data quality over time: practical steps

When it comes to greenhouse gas (GHG) reporting, Scope 3 emissions are often the most challenging part of the puzzle. They cover everything that happens outside a company’s direct operations, from suppliers and logistics to customer use and disposal of products. Because of this complexity, Scope 3 data is often patchy, based on estimates, or scattered across multiple sources. Moreover, most organisations struggle to understand which of the 15 Scope 3 categories within the GHG Protocol are material to their business and hence need to be included in their carbon footprinting calculations.

But here’s the good news: perfection isn’t required on day one. What matters most is building a system that gets better every year. Improving data quality is a gradual process, and each step forward strengthens the accuracy, credibility and usefulness of your emissions reporting.

Start with screening-level estimates

In the beginning, it’s common to rely on spend-based or industry-average data. This approach gives you a directional view of your biggest emission hotspots and helps you identify where deeper analysis is most valuable.

Engage suppliers early

Suppliers are the gatekeepers of a large share of Scope 3 data. Building strong engagement programs from simple surveys to collaborative workshops can unlock more reliable, activity-based data over time. Clear communication about why data is needed and how it will be used can make suppliers more willing to participate.

Shift from estimates to primary data

As relationships and systems mature, move away from generalised databases and focus on primary data from suppliers, business units or a product life cycle analysis (LCA). Even partial primary data in priority categories can significantly improve overall accuracy.

Use digital tools to streamline

Data management platforms can automate data collection, standardise inputs and reduce manual errors. Over time, this integration helps create consistency across your reporting cycle and builds an auditable trail.

Apply quality principles consistently

Follow the GHG Protocol’s five key principles: relevance, completeness, consistency, transparency and accuracy. Document assumptions, keep records of methodologies (i.e. an “Evidence Pack”) and regularly test your data quality against these standards.

Build a roadmap for progress

The key is to plan for improvement year-over-year. For example:

• Year 1: Broad screening with spend-based data
• Year 2: Prioritize top categories and request supplier data
• Year 3: Expand primary data coverage and third-party assurance

This staged approach ensures continuous progress without overwhelming resources.

Takeaway

Improving Scope 3 data quality is a journey, not a one-time exercise. By starting with broad estimates, engaging suppliers and layering in better data and digital tools each year, companies can balance cost and effort while steadily building a reporting system that drives real climate action.