Every month we publish official statistics on NHS activity and performance, including referral‑to‑treatment (RTT) waiting times. These are among the most closely watched figures we produce, because they help patients, clinicians, and policymakers understand how services are performing across Wales.

Darllenwch y dudalen hon yn Gymraeg.

Shortly ahead of our regular publication due 20 November 2025, we identified issues with the RTT data submitted by Betsi Cadwaladr University Health Board (BCU). As a result, we postponed the release and, the next day (21 November), issued a partial publication covering all other areas of activity while we continued to investigate the RTT data concerns.

Since then, we’ve been working intensively with colleagues in NHS Wales and the health board to understand the root cause and the implications for the statistics. We issued a Chief Statistician’s statement to explain the position and wrote to the Office for Statistics Regulation to set out the steps we’re taking.

What the issue is – and why it matters

Our quality checks identified anomalies and inconsistencies in the RTT data submitted by BCU for recent months. Specifically:

• inconsistencies between operational activity and the datasets used for statistics: reported waiting list trends did not align with what operational management information would lead us to expect
• this was due to data coverage problems: some pathways for patients treated by independent providers appear not to have been included in the reported RTT data; the health board has acknowledged issues with how pathways treated by independent providers were recorded
• this led initially to underreporting of patient pathways and meant subsequent reductions in pathways were not reflected in the data

The recent introduction of provisional RTT figures – designed to give users earlier sight of trends – played an important role in identifying these anomalies. The provisional data did not follow expected trends based on operational intelligence, which prompted further checks.

For transparency, our working assumption is that the main issues relate to recent months (particularly August and September), with possible smaller issues earlier in the year. But I should stress that the precise impacts might not be known until a review is complete.

Because RTT statistics are used to monitor performance over time, any coverage gaps or recording errors can make it impossible to say with confidence whether waits are increasing or decreasing from month to month. That is why we took the decision to suspend RTT reporting for BCU while investigations proceed.

What we’re doing to fix it

To provide assurance and to get the underlying data back on a sound footing, the Cabinet Secretary for Health and Social Care has commissioned an external review into BCU’s RTT data quality and governance arrangements. This will examine:

• data collection processes at the health board
• local quality assurance and sign‑off
• reporting practices (including treatment by independent providers)
• governance arrangements supporting these processes

A statistician will be part of the review team to bring expertise in the standards required of official statistics.

While this work is under way, we will continue to publish RTT statistics for Wales excluding BCU, with clear guidance for users on how to interpret the figures when one health board’s data is temporarily absent. We have published the first of these updates today for the statistics that would originally have been published on 20 November.

Our commitment to trustworthiness, quality and value

I recognise how important RTT statistics are to patients and the public, and I take seriously our responsibility to publish figures that meet the standards of the Code of Practice for Statistics – trustworthiness, quality, and value.

How we’re upholding the standards

• Trustworthiness: We acted promptly to postpone publication when concerns emerged, and we have communicated openly through official channels.
• Quality: We have suspended BCU RTT reporting until the independent review concludes and we have confidence in the data. We are providing advice to users on how to interpret recent RTT statistics in light of this issue.
• Value: To meet user need, we are continuing to publish all other parts of the monthly NHS activity and performance release and will publish RTT for Wales excluding BCU until reliable data is available.

At this stage, we have not withdrawn any previously published data, despite recognising that some recent months may be affected by the identified issues. Instead, we are offering clear guidance to users on how this data should – and should not – be interpreted and used. We are hopeful that the quality concerns can be resolved swiftly; however, should the review take longer than anticipated or reveal a wider impact, we may reconsider this position and withdraw the affected data in the future.

Importantly, our quality assurance processes have not identified similar issues with other health boards’ RTT data. We will keep this under review and remain transparent if anything changes.

What happens next

Our focus is on restoring full coverage for Wales as quickly as we can once we are confident in the data. We are working closely with NHS Wales colleagues and BCU to address the underlying issues, and we will update users through our normal statistical channels the moment we are ready to resume all‑Wales RTT reporting.

If you use RTT statistics in your work and have questions about interpretation while BCU is excluded, we welcome your feedback and will do our best to help.

Stephanie Howarth
Chief Statistician