M&A Note 2/2008

Users of official statistics often express concern about definitional differences between statistics for the four UK administrations. This problem most commonly arises where each administration draws its own statistics from administrative systems which operate slightly differently in each country. The standards and classifications adopted will usually reflect the specific legislation, practice and policies in each country and the ways these have developed. This means that the differences are sometimes deeply embedded and there is little prospect of resolving them by proposing changes to administrative procedures in one or more country.

Statistics from National Health Service systems are one example where administrative differences can lead to statistical inconsistency. Such inconsistency then hampers analysis – including analysis of the differences in administrative practice.

In its 2004 report ‘Enhancing the Value of Health Statistics: User Perspectives’, the Statistics Commission noted the problems arising from a lack of standardisation in health statistics between the four administrations. In particular it highlighted a lack of comparability in statistics about waiting times for treatment, and recommended further research to examine the most effective means of harmonising the data.

This Monitoring and Assessment Note highlights subsequent developments in the production and reporting of comparable waiting time data by the relevant statistical offices in England, Wales, Scotland and Northern Ireland. It illustrates a ‘non-invasive’ approach that supports analysis without requiring change in NHS administrative practice or statistical arrangements. As such it may offer a model that could be adapted to other fields.

The statistical offices in the four administrations established a UK Comparative Waiting Times Group, which commissioned a review of waiting time definitions in each of the administrations and then undertook a project to produce harmonised data. A table of comparable waiting times in the four countries was published for the first time in the United Kingdom Health Statistics volume in 2008.

A list of 11 inpatient procedures was selected for analysis on the basis of both volume of cases and data quality within each country. A common definition was adopted for the analysis – being the time a patient had waited from the initial decision to admit to the date of admission for the procedure, including periods of suspension for medical and social reasons. This measurement differs from the waiting time targets which typically exclude periods of suspension from the estimates. Equivalent measures were adopted of median completed waiting time in days and the time within which 9 out of 10 patients were admitted using a consistent base year.

The health services in each administration are establishing new ways of handling the referral of patients for treatment. To support these, new methods of data collection are being set up that will enable the full ‘referral to treatment’ period to be measured. These developments provide a further opportunity for harmonisation but will require the administrations to work together to develop a consistent framework for a common patient journey and processes for the integration of future data collections.

The UK Statistics Authority recognises as good practice the work undertaken to improve the comparability of waiting time data by the four statistical departments. The Authority considers that a similar approach could be used to improve the comparability of other sets of figures where inconsistencies exist, although it also recognises that some users will only want (non-harmonised) statistics that reflect the particular arrangements in one or more administration.

One of the first statistical areas that will be assessed by the Authority against the Official Statistics Code of Practice (which will be published in January 2009) will be statistics of children looked after by local authorities across the UK. This assessment will include an examination of the comparability of the data relating to the four administrations.

Statistics Commission: Report No 21: Enhancing the value of health statistics: User perspectives

System Concepts review: Comparison of UK waiting times definitions

http://www.dhsspsni.gov.uk/uk_comparative_waiting_times.pdf UK Health Statistics 2008: