Who must submit a methodology
Online marketplaces must submit a methodology by 1 April for the previous calendar year. A marketplace that reports 2025 data must submit its methodology by 1 April 2026.
Other obligated producers do not have to submit one under current guidance. A written methodology still provides evidence during an audit and protects the reporting process when staff or suppliers change.
What the document should contain
Scope and ownership
State which products, packaging activities and reporting periods the methodology covers. Name the people who collect, review and submit the data. Explain exclusions such as exported packaging.
Data collection
List each data source, including supplier specifications, product records, samples and order data. Describe sample sizes, weighing equipment and checks applied to supplier figures.
Estimates and missing data
Record the rule used when measured data is unavailable. Keep the source, calculation, approval and date for each assumption. Explain how the team plans to replace estimates with measured data.
RAM assessments
Describe how the team assessed each packaging item or component, retained evidence, handled medical packaging and controlled assessment versions. Record how long you retain the supporting data.
Add controls an auditor can test
Reconciliation
Compare reported mass with sales, purchasing or import totals and explain material differences.
Version control
Keep prior weights, approvals and report versions instead of overwriting the audit trail.
Quality review
Name the reviewer, the checks completed and the date of approval.
Supporting evidence
Retain sample results, supplier records, anomalies and RAM assessment evidence.
Map each reported field to its source
Add a data-lineage table to the methodology. It should show where each field starts, which transformation applies and who reviews the result.
| Reported field | Source | Transformation | Control |
|---|---|---|---|
| Packaging mass | Specification or sample | Grams multiplied by supplied units | Sample and unit check |
| Material | Component specification | Map to accepted code | Exception report |
| Activity | Brand, import and supply records | Apply scope rule | Compliance review |
| Nation | Delivery or sales data | Aggregate by required method | Reconcile to orders |
| RAM rating | Assessment record | Map outcome to RPD code | Evidence and approval |
Write a reproducible sampling method
Name the population, selection rule, sample size, equipment and rounding method. Explain why sampled products represent the wider group. Keep raw measurements and record outliers instead of deleting them without explanation.
Set a trigger for new sampling, such as a supplier change, redesign or variance outside the approved tolerance. State who can approve continued use of the existing result.
Maintain an improvement register
List missing specifications, old estimates and manual calculations that create reporting risk. Assign an owner and target date. At the next review, record whether the team closed the issue or accepted it with a reason.
Review and submit
Review the methodology at least once in each reporting cycle. Update it when suppliers, products, materials or classification rules change. Online marketplaces can send the document to the environmental regulator using the submission route in current GOV.UK guidance.
Remedy EPR keeps packaging specifications, estimates, RAM evidence and report versions in one controlled record.
Prepare accurate EPR reports without rebuilding spreadsheets
Remedy EPR automates data imports and calculations, detects compliance errors and keeps evidence ready for review.
Primary source: GOV.UK methodology guidance. Confirm current requirements before submission.