What constitutes activity data versus emission factors and when should primary d

Activity data are quantitative measures of operations (e.g., kWh consumed, liters of diesel, ton-km shipped). Emission factors translate that activity into GHG emissions using coefficients reflecting fuel properties, processes, or supply chain models. Prioritize primary (supplier- or site-specific) data where emissions are material, variable, or decision-critical—such as energy-intensive sites, high-leakage refrigerants, or strategic suppliers—because it improves accuracy and enables targeted reductions. Secondary data (industry averages, databases) remain appropriate for low-materiality categories or early baselines. Implement a data quality framework assessing temporal, geographic, and technological representativeness, completeness, and precision; use it to triage where to upgrade to primary data. Record provenance (source, version, publication date) for all factors, and implement review cycles tied to updates from authoritative sources (e.g., IPCC, EPA, IEA). For Scope 3, engage suppliers through CDP or contract clauses to obtain facility-specific electricity, fuel, or process data, and incorporate assurance-ready evidence (utility bills, metering exports). Clearly flag modeled vs measured data in the tracker and propagate uncertainty to inform confidence intervals on totals and intensities. Key Takeaway: Use primary data where material or variable; manage factors with strict provenance and data-quality controls to drive accuracy and actionability.