Read the basis beside the result
A result describes a particular product version, reference amount, model and calculation run. Start by checking those records. Confirm the question being answered, the selected impact category and its unit, and the conditions under which the product is assessed. The European Commission describes goal and scope, inventory, impact assessment, and interpretation as distinct phases of a PEF study. [1]
The functional unit describes the quantified function under study. The reference flow connects that function to the product amount required in the model, as explained in JRC's ILCD Handbook. [3] Review the approved description and amount together. The openLCA manual states that a product system's target amount should follow its functional unit. [2] Laiffi records the reference product, amount, unit and description in the calculation configuration.
Check the selected lifecycle boundary
The system boundary records which activities the assessment covers. Laiffi organises lifecycle coverage into raw material supply, manufacturing, packaging, distribution, use and end of life. Its presets select the stages shown below. Treat the preset as a starting selection, then review the included activities and recorded exclusions for the actual assessment.
A stage selection does not establish that every relevant activity has a quantified input. Check the inventory review and limitations after checking the boundary. The practitioner must also resolve allocation, recycling, background modelling and other methodology choices where they apply.
| Laiffi preset | Stages selected in the application |
|---|---|
| Gate-to-gate | Manufacturing |
| Cradle-to-gate | Raw material supply, manufacturing and packaging |
| Cradle-to-grave | All six lifecycle stages |
Read what each coverage status means
Lifecycle stage coverage describes the selected run. Read the status with its quantified exchange count, quantity evidence, dataset fit and recorded evidence. The table below explains the states used in Laiffi. A count tells you what the model contains; it does not prove that the inventory is complete.
| Status | How to read it |
|---|---|
| Quantified in this run | The run contains quantified exchanges for this stage. Review their extent and dataset fit. |
| Quantified with proxy or estimate | At least one quantity uses a proxy, estimate or assumption, or a linked dataset is marked as a proxy. |
| In boundary, justified no direct activity | The review records a basis for having no direct exchanges in this stage. Read that basis. |
| In boundary, excluded from subtotal | The selected boundary includes the stage, but the run has no quantified exchanges for it. |
| Excluded from this run | The inventory review records a stage exclusion. Read the rationale and any related limitations. |
| Recorded evidence only | The run records evidence for the stage but has no quantified exchanges for it. |
| Not assessed | The run has no quantified exchanges, recorded stage evidence or reviewed stage exclusion. |
Review quantity evidence and dataset fit separately
A measured quantity may still be linked to a proxy background dataset. Conversely, a representative dataset may be multiplied by an estimated product quantity. Laiffi records quantity evidence and dataset representativeness separately, so inspect both before accepting the input's contribution.
For each material or energy input, follow the trace to the mapping decision, dataset and source record. Check the dataset context and the reason for its selection. JRC's data quality guidance considers technology, geography and time representativeness. [3] In Laiffi, a dataset marked as not assessed still needs a recorded assessment of its fit.
Keep omissions attached to the subtotal
When an activity remains unmodelled, the displayed subtotal covers the quantified model. Keep the missing activity and its significance visible when using that number. Review the full calculation basis, source questions and limitations as well as the stage table. The stage table lists exclusions recorded in inventory review and may not contain every source limitation.
JRC's ILCD Handbook requires practitioners to document cut-offs and reflect gaps in interpretation. [3] Review any proposed exclusion against the assessment purpose and agreed criteria. Missing evidence alone does not establish an activity's insignificance.
Impact assessment coverage also depends on the selected method. The openLCA manual explains that some inventory flows may lack characterisation factors in that method. [4] Ask the practitioner to check relevant unmatched flows and record what they mean for the result.