Start with the decision
Choose a factor only after defining the activity and its units. A transport activity, electricity purchase and product-manufacturing question need different data. A familiar factor name does not establish suitability for every material or geography.
Build the record
Record source URL or document, factor identifier, value, units, year, geography, method and licence conditions. Keep the original activity quantity and conversion steps. Distinguish data-year information from publication date. Where a factor is an assumption or proxy, label it and explain the limitation.
Check before acting
Check dimensional consistency and relevant scope before multiplying. Retain the factor version used for a decision, then review current availability when updating a scenario. Government reporting factors can support suitable activity reporting; a missing exact-product manufacturing factor remains missing. Never derive a product number simply by relabelling a generic category.
Worked example — illustrative
A fictional worksheet imports a transport factor whose unit differs from the distance input basis. The analyst records activity quantity and conversion and checks applicability before recalculation. The factor remains tied to its version. A later update produces a new scenario instead of overwriting the historical calculation.
Keep a useful handover
Record the responsible person, decision date and next review trigger with the evidence version. Keep planned actions distinguishable from confirmed activity. If later information changes the result, preserve the earlier record and update current guidance.
- Match the activity.
- Retain identifier and units.
- Record geography and period.
- Explain proxies.
- Version recalculations.