Last year we investigated the methodologies of the NHS waiting list statistics produced by the four nations of the UK, and reported initial conclusions on the comparability of the headline performance measures.
Darllenwch y dudalen hon yn Cymraeg.
We found coverage differences in the data were significant enough to mean none of the headline figures for pathways waiting were directly comparable between any of the nations, although an adjusted measure can be produced for Wales to be broadly comparable with England.
That exercise was focused on the total figures for Referral to Treatment (RTT) pathways waiting based on the official administrative data. In this blog post we look at an alternative source on patients waiting for NHS services, and present findings on comparability for some of the subsets of total waiting lists as well as data on the amount of time spent waiting.
Survey estimates of patients waiting
The Office for National Statistics (ONS) provides estimates on people waiting for appointments, tests or treatment through the NHS in England, Scotland and Wales through the Opinions and Lifestyles survey (OPN). This is based on a survey from a sample of the population where responders self-report , rather than administrative data taken from NHS systems. The questions also have a broader coverage than the official statistics, which are generally limited to consultant led activity. Northern Ireland is not included in the OPN.
The estimates show that in February 2023:
- 29% of respondents in Wales said they were currently waiting for a hospital appointment, test or treatment through the NHS
- for Scotland the estimate was 25%, and for England it was 21%
The estimates are uncertain for Wales and Scotland because of small sample sizes, so we should interpret these figures with some caution. But in contrast with the official statistics on waiting lists, these estimates are directly comparable across the nations. They imply the relative differences between the nations when all types of pathway are counted may be smaller than suggested by the official administrative data, which in general just count those that are consultant led.
Apart from the total number of patients waiting, can other comparisons be made?
Turning back to the official measures on pathways waiting, the official Welsh statistics (StatsWales) are available for four stages of patient pathway.
These are people waiting for:
- a new outpatient appointment
- a diagnostic or Allied Health Professional test, intervention or result
- a follow up outpatient or appointment
- admitted diagnostic or therapeutic intervention (treatment)
We have investigated the availability of comparable data across the UK for each of these stages. Conceptually, the stages appear similar to some of the figures published by other nations. However, as with the overall RTT statistics, there are differences in coverage and definitions, meaning in most cases they are not directly comparable.
First outpatient appointment figures are not available for England, and for Scotland they do not include significant parts of the pathway that are counted in Wales. For Northern Ireland however, figures for patients awaiting first outpatient appointments are available and are judged to be on a comparable basis to the Wales figure.
As of June 2023:
- there were 416,000 recorded open pathways awaiting a first outpatient appointment in Northern Ireland, equivalent to around 22 pathways per 100 people
- in Wales, there were 422,000 first outpatient appointment waits, equivalent to around 14 pathways per 100 people
None of the other nations produce figures equivalent to the second and third stages of pathway reported in Wales, but all nations publish statistics for patients awaiting treatment as an inpatient or day case. However, due to differences in coverage, these shouldn’t be compared across the UK. Figures for Northern Ireland are suspected to include some duplication. For Scotland and England, only cases where a decision to treat has been made are counted, whereas in Wales figures include patients for whom a decision to treat has not yet been made. Consequently, the published statistics for the four nations for these stages of patient pathway are not regarded as comparable.
Waiting times
As well as figures for the number of pathways waiting, the four nations also publish statistics on waiting times. The methods for calculating waiting times are very similar in each country, however, the waiting times targets are different, reflecting local policies and needs. For example in England patients have a right to start treatment within 18 weeks of referral and in Wales 95% should start treatment within 26 weeks. In Scotland all patients should start treatment with 12 weeks of a decision to treat and in Northern Ireland 55% should start treatment within 13 weeks of a decision to treat. There are also various other targets across the four nations relating to outpatient appointments, diagnostics and therapies, all of which are unique to each country. Consequently, the published performance measures can’t be used to directly compare waiting times across the nations.
Despite these differences, it is still possible to draw some high-level conclusions about waiting times over a year in each nation. As Table 1 shows, figures on pathways waiting more than one and two years do suggest some significant differences in waiting times between some of the nations.
Table 1. Pathways waiting more than one and two years by UK nation, March 2023
| Pathways waiting more than 1 year | Pathways waiting more than 2 years | |
| Wales | 133,000 | 28,000 |
| Scotland (outpatient and inpatient / day case stages only) | 74,000 | 8,000 |
| England | 383,000 | <1,000 |
| Northern Ireland | 267,000 (outpatient and inpatient / day case stages only) | 123,000 (outpatient stage only) |
Although we know these figures aren’t entirely equivalent to each other and should not be directly compared, the methodological differences cannot account for the scale of some of the differences in the numbers waiting longer than one and two years. This is particularly the case when taking into account the much larger population of England.
Additionally, OPN survey data also provide strong evidence on waiting times. OPN does not cover Northern Ireland, but estimates that in February 2023, 49% of people waiting in Wales had been waiting for longer than one year, compared with 23% in Scotland and 18% in England. As stated earlier, OPN figures are directly comparable between the nations, though the estimates have a wider range of uncertainty for Wales and Scotland in particular because of small sample sizes. They relate to all types of NHS waits, not just consultant-led pathways.
What we’re doing to understand more
There are likely to be further differences in coverage and definitions between the nations which we cannot yet measure with confidence. However, these are likely to be on a smaller scale than the differences described in this and previous blog posts and to the best of our knowledge are unlikely to materially affect the statistics.
There continues to be considerable interest in statistics on NHS activity and performance across the UK. As we have done in this blog post, we continue to work with the ONS and other UK nations to investigate coherence and comparability with waiting list statistics, but also on other topics including emergency care, ambulance response, cancer services, patient experience, workforce numbers and health outcome measures. This work will provide a greater level of understanding of similarities and differences in health statistics and will support users of these statistics in making meaningful comparisons. Over time we will provide further updates either via this blog, or through statistical reports on these topics.
Stephanie Howarth
Chief Statistician