How to Estimate Missing Data for CSRD Reporting

Introduction

Every SME preparing a CSRD report eventually faces the same problem: some data is missing. Maybe an energy bill is lost, a supplier hasn’t responded, or older records were never tracked. The good news? The CSRD and VSME frameworks both allow estimation — as long as it’s transparent, consistent, and based on reasonable assumptions.

This guide shows how to fill data gaps responsibly while staying compliant with the Corporate Sustainability Reporting Directive (EU 2022/2464) and EFRAG’s VSME Standard (2024). You’ll learn which data can be estimated, how to choose a suitable method, and what documentation auditors expect.

If you’re still setting up your data workflow, read our practical guide on integrating CSRD data collection into existing workflows first.

1. When Is Estimation Acceptable?

The CSRD Directive recognises that not all data is available in full detail, particularly for SMEs or in early reporting years. Estimation is acceptable when:

• Source data is temporarily unavailable (e.g. missing invoices).
• Data from suppliers or subsidiaries cannot be obtained in time.
• You’re reporting on new indicators for which historical data doesn’t exist.

In all cases, you must disclose that estimation was used and briefly explain how it was calculated.

The VSME Standard also explicitly encourages “good faith” estimations based on credible, verifiable sources — such as invoices, standard conversion factors, or average activity data.

2. Identify What Data Is Missing

Start by reviewing your data map or reporting template to see where information is incomplete. Common gaps include:

• Monthly or quarterly energy bills
• Business travel fuel receipts
• Waste collection weights or recycling rates
• Employee turnover or absence rates
• Supplier emissions (Scope 3 data)

Flag these gaps clearly and prioritise those that have the biggest impact on your results — for example, energy or fuel data typically affects multiple ESRS disclosures.

3. Choose the Right Estimation Method

Different data types call for different estimation approaches. Below are practical methods suitable for SMEs:

Always prefer measured data where available and clearly mark which figures were estimated.

For help aligning these categories with your broader timeline, see our annual CSRD reporting calendar.

4. Document Your Assumptions

Transparency is key. When using estimated data, note:

• Why estimation was needed (e.g. missing invoice, unavailable data).
• How the estimate was made (method, data source, assumptions).
• Who approved the method and when.
• When actual data will replace the estimate (if applicable).

Example disclosure statement:

“Energy use for Q2 2025 was estimated using the average of Q1 and Q3 consumption, as invoices were unavailable due to supplier change.”

This simple documentation step satisfies the CSRD’s requirement for traceability and strengthens assurance readiness.

5. Validate and Refine Your Estimates

Estimates should be reviewed for plausibility:

• Compare totals to prior-year data or industry benchmarks.
• Check that estimated figures don’t distort your performance trends.
• Adjust future estimates as better data becomes available.

Auditors generally accept estimations that are logical, supported by evidence, and consistent over time.

6. Reduce Data Gaps Over Time

The goal isn’t to estimate forever — it’s to reduce reliance on estimation each year. To achieve that:

• Automate utility and HR data collection through existing systems.
• Ask suppliers to provide ESG data proactively.
• Maintain centralised digital storage for invoices and receipts.

These steps make next year’s CSRD or VSME report faster, more accurate, and less stressful.

Frequently Asked Questions

How much estimated data is “too much”?

There’s no fixed limit, but auditors generally expect at least 70–80% of your key data to be actual. Estimate only where unavoidable, and disclose clearly.

Can I use industry averages?

Yes, but cite your source (e.g. Eurostat, national energy databases, or sector reports). Industry benchmarks are acceptable for small companies under VSME guidelines.

What if I find better data later?

You can update or restate figures in your next report. The CSRD allows for corrections and restatements, provided you explain the reason for the change.

Do estimates need assurance?

Yes, but only in the sense that your methodology must be verifiable. The auditor won’t re-create your estimate — they’ll check if it’s reasonable and consistent.

Key Terms

• Estimation – Approximating missing sustainability data using transparent and reasonable methods.
• Traceability – The ability to link each data point to its source or calculation method.
• Scope 3 emissions – Indirect emissions from suppliers, transport, or waste.
• Materiality – Determining which sustainability topics have significant impact or relevance.
• Assurance – Independent review of reported sustainability information for accuracy and completeness.

Conclusion

Missing data shouldn’t stop you from publishing your CSRD or VSME report. What matters is that your estimation method is transparent, logical, and well documented. Start with simple averages or benchmarks, explain your reasoning, and improve your process each year.

For a full walkthrough of how to structure your reporting process from start to finish, see our guide on how to build a CSRD reporting system from scratch.

Before estimating missing data, it’s helpful to have a complete checklist of all data points you should be collecting. Use our checklist generator to identify what data you need and spot any gaps:

This will help you systematically identify what’s missing and ensure you’re tracking all necessary data points going forward.