Primary emissions data is directly reported or measured from the source, such as a supplier's verified energy consumption or actual emissions. This offers the highest accuracy and clear provenance for auditable reporting. Secondary emissions data, by contrast, relies on estimates, averages, or industry benchmarks to approximate emissions when direct data is unavailable. While secondary data provides necessary coverage, DitchCarbon prioritises collecting verified primary data to ensure the most credible and actionable Scope 3 calculations.