Research indicates that the UK’s gender pay gap has been underestimated for over two decades, calling into question the data quality used for critical pay decisions. This study, published in the British Journal of Industrial Relations, asserts that since 2004, the Office for National Statistics (ONS) has failed to adequately account for the prevalence of data from larger employers in its annual survey of hours and earnings (Ashe).
This oversight has resulted in an overrepresentation of larger businesses, where wages tend to be higher and the gender pay gap smaller, while smaller businesses—where disparities may be more pronounced—received less focus. This has led the ONS to consistently underestimate the gender pay gap by an average of one percentage point.
Professor John Forth, the lead author of the study from Bayes Business School at City St George’s, University of London, noted that the findings have significant implications, as the data informs various societal issues, from salary recommendations for public sector workers to national minimum wage policies. The credibility of such data is crucial for accurately reflecting wage structures in contemporary Britain.
The Ashe survey is utilized by the Low Pay Commission to evaluate minimum wage effects and by the Office for the Pay Review Bodies to establish public sector pay rates. This revelation adds to a series of challenges faced by the ONS, which has recently encountered issues that have led to delays or cancellations of several report releases.
The ONS did not immediately respond to inquiries but informed the Financial Times that it is currently reviewing the sampling and weighting of the survey, stating that improvements made since 2024 aim to address the report’s criticisms. Forth expressed support for this review process, encouraging the ONS to enhance the representativeness of the data across different types of organizations.
Source: https://www.theguardian.com/world/2025/aug/25/uk-gender-pay-gap-underestimated-for-two-decades-report-says