What’s the minimum sample size for pay gap reporting, and what if we don’t meet it?

The EU Pay Transparency Directive doesn’t set a hard minimum group size for pay reporting. But the general principle is clear: avoid reporting on groups so small that individual employees could be identified. If a group is too small, aggregate it with others or apply privacy protections.

There’s no single EU-wide rule for minimum group size. Instead, employers are expected to apply good judgment and align with broader data protection principles (such as GDPR). 

Common guidance includes: 

• Avoid publishing data for groups with fewer than 3–5 people.
• Aggregate small groups into broader job families or categories.
• Use anonymisation techniques (e.g. masking figures). 

When employees request pay comparisons: 
Even if formal reporting isn’t possible for small groups, employees may still ask for average pay levels. In those cases, employers should: 

• Share aggregated averages, never individual salaries.
• Be transparent about why some data is withheld.
• Explain how pay relates to established salary bands. 

Under Irish law, employees have the right to equal pay for equal work, but there is no current formal mechanism for requesting average pay comparisons outside of the reporting framework. Employers should handle such requests with care, ensuring privacy and consistency with internal pay structures. 

Other considerations: 

• Small samples can distort results, making gaps look bigger or smaller than they really are
• Rolling averages or multi-year comparisons can help smooth spikes
• Don’t rely on employee “consent” to share pay data. Under EU law, consent in employer–employee relationships isn’t considered valid. 

To manage small group data, employers should: 

• Define clear minimum thresholds for reporting.
• Build aggregation and anonymisation techniques into reporting systems.
• Prepare managers to explain why some information can’t be shared, without undermining employee trust. 

See also: Which employees are included in the scope of the Directive?

Protecting privacy while being transparent is a delicate balance. Handling small groups carefully keeps reporting credible and compliant, without exposing individual pay data. 

In Ireland, the Gender Pay Gap Information Act 2021 does not set a minimum sample size for reporting. However, employers are expected to apply GDPR principles and avoid publishing data that could identify individual employees. Where groups are small — typically fewer than 3-5 people - it’s usually best practice to use anonymisation techniques. While employees may raise questions about pay fairness, there is no formal right to request average pay data outside the reporting framework. Employers should ensure that any disclosures are consistent with internal pay structures and privacy obligations.  

Done right, this reassures employees that pay transparency is about fairness, not exposure.