Start with the product and the question
Identify the product version you want to assess before collecting files. Record its name, revision, manufacturing location and the question the assessment should answer. A design comparison, a supplier discussion and an external report may need different evidence. Tell the practitioner who will use the result and what decision they need to make.
Keep the assessment basis with this brief. If a functional unit, reference amount or system boundary has already been agreed, include the record of that decision. If it is unresolved, flag it for review. The European Commission places goal and scope definition before inventory compilation in its description of a PEF study. [1]
Gather the files you already use
Begin with the current bill of materials and the evidence behind it. Keep item codes and product revisions so the reviewer can connect a row to the right component. Add manufacturing records and other evidence for activities relevant to the proposed scope. Keep original files alongside any working copies you prepare.
The table below is a collection checklist. It does not mean every record belongs in the calculation. The inventory review determines which records describe quantified inputs, context, duplicates or unresolved questions.
| Evidence to gather | Context to keep |
|---|---|
| Bill of materials | Item code, material description, quantity, unit and product revision |
| Manufacturing inputs | Facility, process, measurement period and quantity basis |
| Packaging records | Packaging item, material, quantity and the product it accompanies |
| Transport records | Origin, destination, mode and any documented distance or load basis |
| Use and end-of-life evidence | Applicable product, source, conditions and stated assumptions |
Explain what each quantity measures
Every quantity needs a unit and a basis. State whether a material amount describes one component, one finished product or a batch. For manufacturing energy, keep the period and production output behind the measurement. A factory total needs a documented treatment before it can represent a product input.
Preserve the reported value even when you prepare a normalized value. Keep the conversion and its evidence available for review. A component count and a material mass describe different things. Converting between them requires supporting information. The openLCA manual associates flows with a reference flow property, such as mass or volume, so a unit must fit the quantity being modelled. [2]
Keep the context behind manufacturing data
Record the operation, facility and product or component to which an input applies. If you have a manufacturing route, keep the step order and the evidence for each operation. An operation name alone does not provide its energy use, material loss or emissions. Keep those quantities separate from the route description.
The Commission distinguishes data collected for processes an organisation operates from secondary data commonly used for upstream processes. [3] Send the measurements and supplier information you have. The practitioner can then review the background dataset needed to represent the associated supply chain.
Make each input traceable to its source
Keep the source file name, revision and the row, sheet, record or page that supports each input. Include the document date and measurement period where available. If a supplier sends a correction, retain the original record and identify what changed. This lets a reviewer follow a normalized input back to the evidence.
Separate measured quantities, supplier estimates, assumptions and proxies in your notes. Also record where and when the information applies. JRC's ILCD Handbook treats technological, geographical and time representativeness as data quality considerations alongside completeness, precision and methodological consistency. [4]
List the gaps while they are still visible
Create a short list of missing quantities, unclear units, conflicting revisions and activities that have evidence but no quantified input. Give each question an owner or an evidence request where possible. Keep a missing value blank and describe the gap. Any estimate used later needs its own basis and review.
A material name can help find candidate background datasets, but the mapping also needs context. Retain material specifications, supplier geography and process information where documented. Leave the dataset decision for review when the evidence does not support a match.
Prepare the handoff for review
Send the product brief, source files and gap list together. Point out shared factory measurements, possible duplicate inputs and evidence that applies to several product versions. These details help the practitioner resolve meaning and coverage before approving the inventory.
- Confirm that the files describe the selected product revision.
- Check that each supplied quantity has a unit, basis and source reference.
- Identify assumptions and estimates in the same place as the inputs they affect.
- Attach the unresolved questions and the next evidence needed to answer them.