How Accurate Does CSRD Data Need to Be?

Introduction

When you start collecting data for your first CSRD or VSME report, one of the first questions you’ll face is: “How accurate does this data really need to be?”

The short answer is: your data must be reasonably accurate, verifiable, and consistent over time — not perfect. The Corporate Sustainability Reporting Directive (EU 2022/2464) recognises that many small and growing businesses (SMEs) are building their systems for the first time. What matters most is transparency about how the data was collected, and whether it’s reliable enough for limited assurance review.

This guide explains what “reasonable accuracy” means in practice, how auditors check it, and how to improve data quality over time without overcomplicating your reporting process.

If you’re still working on your data collection systems, start with our guide on how to integrate CSRD data collection into existing workflows.

1. What “Accuracy” Means Under CSRD

CSRD data must be reliable and free from material misstatements, but it doesn’t need to be perfectly precise. The Directive requires companies to report using methods that are:

• Consistent – The same calculation methods should be applied year-on-year.
• Traceable – You can show where each number came from (invoice, system, estimate).
• Reasonable – The data fairly represents your actual performance or impact.

For SMEs following the VSME Standard, EFRAG explicitly allows “best available data” and reasonable estimations where detailed measurement is impractical. The expectation is progress — not perfection — in your first few years of reporting.

2. What Level of Assurance Applies

From 2024 onwards, CSRD reports must undergo limited assurance, meaning auditors will:

• Check that your data is plausible and internally consistent.
• Verify that you’ve disclosed your sources and assumptions.
• Ensure figures align with financial data (e.g. energy spend matches reported energy use).

Limited assurance provides moderate confidence — it’s not a full audit like “reasonable assurance,” which may become mandatory in later years.

Under the VSME Standard, assurance is voluntary but encouraged for companies seeking external validation or improved credibility.

To learn how to prepare for review, see our guide on how to prepare for your first CSRD audit or review.

3. Acceptable Estimation and Approximation

If you don’t have precise measurements, you can estimate using credible methods such as:

• Invoice-based averages (e.g. average kWh/month).
• Industry benchmarks (e.g. emissions per employee or per € of turnover).
• Supplier data for material inputs or travel.
• Reasonable assumptions supported by documentation.

For instance, if you lack electricity data for one quarter, estimate it using neighbouring months or annualised averages — as long as you explain the method.

You can find more detail in our guide on how to estimate missing data for CSRD reporting.

4. When Accuracy Becomes a Problem

Auditors and regulators don’t expect zero errors, but they do flag issues when:

• Estimates are not disclosed or supported by evidence.
• Figures change dramatically year-on-year without explanation.
• Energy, HR, or financial data are inconsistent across sections.
• Results seem implausibly precise (e.g. reporting CO₂ emissions to six decimal places).

Remember: reasonable accuracy beats false precision. The key is clarity about uncertainty, not the illusion of exactness.

5. Improving Accuracy Over Time

CSRD reporting is designed as an iterative process. Each reporting cycle should strengthen your systems and data confidence.

You can improve accuracy by:

• Automating data collection from finance, HR, and utility systems.
• Keeping documentation of assumptions, sources, and calculation methods.
• Regularly cross-checking sustainability data with financial records.
• Asking suppliers for primary data instead of using averages.

Most SMEs move from 70% estimated data in year one to 90% measured data by year three — a natural improvement curve fully consistent with CSRD expectations.

Frequently Asked Questions

Do all numbers need to be 100% exact?

No. You just need to show that they are reasonable, traceable, and consistent. Minor rounding or estimation is perfectly acceptable for SMEs.

What happens if my data turns out to be wrong later?

You can correct or restate figures in your next report. The CSRD encourages continuous improvement rather than penalties for honest errors, provided they’re disclosed.

How precise should my emission factors or conversion data be?

Use the latest official factors (e.g. EEA, DEFRA, or ADEME) and round to a practical level (one or two decimals). Consistency across years matters more than excessive detail.

Will auditors reject my report if I estimate?

No — estimation is allowed, as long as you clearly explain the method and source. Transparency is the core compliance principle.

Key Terms

• Limited assurance – Moderate-level audit verifying plausibility and consistency of reported data.
• Reasonable assurance – Higher-level audit, similar to a financial audit.
• Material misstatement – An error significant enough to change the report’s interpretation.
• Traceability – Ability to link data to its source or supporting evidence.
• Proportionality – Allowing SMEs to apply simplified, reasonable methods due to size and capacity.

Conclusion

CSRD reporting doesn’t demand perfect precision — it demands credible, transparent data. For SMEs, accuracy means using your best available information, explaining any estimates, and improving year by year.

By focusing on traceability and reasonableness rather than mathematical exactness, you’ll meet both the letter and the spirit of the CSRD.

For next steps, explore our annual CSRD reporting calendar to plan when and how to gather verifiable data throughout the year.

To help you collect accurate data from the start, use our checklist generator:

This tool will help you identify all the data points you need to collect and ensure proper documentation for accuracy.